Mysteries of the Abandoned - Episode Guide

Revisiting deserted engineering projects to find out how they were built and why they were mysteriously abandoned; a Soviet mega-structure; a massive Nazi brainwashing complex; a dangerous desert pass.

Some of the world's most incredible engineering projects are now deserted; explore a ghost town that was once a dangerous industrial hellscape, a giant warship at the bottom of the ocean, and a top secret relic that could have changed the Cold War.

Some of the world's most incredible engineering projects are now deserted; explore what happened to the large town located just outside of Chernobyl on the eve of disaster, a fleet of ghost ships, and a dangerous mountain road that changed history.

Stories of incredible engineering projects now deserted, including a massive military site that was once a hotbed for nuclear testing, a top-secret airbase hidden inside a mountain, and an otherworldly power plant.

Abandoned engineering projects include a classified Soviet machine built to prevent all-out nuclear war, a top-secret Nazi facility, and a strange tower that left an enduring legacy.

Some of the world's most incredible engineering projects are now deserted; Explore what happened to a cutting-edge research complex built by a visionary genius; an ambitious Nazi project that met a sinister end; a Cold War relic that changed history.

A strange Cuban prison, an eerie escape route built for Armageddon, and an underwater marvel that changed history are mysterious deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A mysterious American pyramid built out of Cold War paranoia, a haunted prison, and a cluster of structures in the Atlantic are mysterious deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

Traces of a Russian hole to hell in the Arctic, a military base in America's wild west, and a strange looming tower are mysterious, deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A secret Russian military base in the Gobi Desert, a strange complex in an American wasteland, and a relic high atop a mountain are mysterious deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A secret structure on a sinister mountain, an industrial compound swallowed by a forest, and a mysterious run in a sand dune are strange deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A strange alien shrine on a mountain peak, a bridge built in the Alaskan wilderness, and an American castle with a dangerous secret are mysterious deserted engineering projects. New discoveries reveal how they were built and why they were abandoned.

An American ghost town in the Amazon jungle, a secret Nazi base, and a deadly concrete fortress 866 miles long are mysterious deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A terrifying sea fortress, a highway in the Amazon that suddenly vanishes, and a mysterious structure in the shadow of the Statue of Liberty are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

Eerie ghost ships stranded in an alien desert, sinister ruins known as the Dragon's Teeth, and a ghostly complex with a bloody past are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A ghost ship thousands of miles away from where anyone expected, a bridge to nowhere in Florida's Hurricane Alley, and a haunting mountain complex with a bloody secret are deserted engineering projects. New discoveries reveal how they were built and why they were abandoned.

An alien Nazi structure that changed history, a strange Soviet monolith known as the Tower of Death, and a concrete ocean giant are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

An entrance to the underworld in the American wild, a haunting Soviet underwater prison, and a strange complex of towers in a forest of ice are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A strange deserted city in America's heartland, an eerie gigantic wall deep in snowcapped mountains, and a mysterious top-secret Soviet facility are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A deserted town in Spain with a bloody past and a ghost fleet heading nowhere are homes to dark American secrets, and new discoveries reveal how they were built and why they were abandoned.

A haunted lighthouse on Lake Michigan, a town where everyone seems to have vanished all at once, and a secret complex of tunnels beneath London are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

A Nazi fortress that could have changed history if it was finished, an underwater graveyard of unexpected American treasures, and a network of tunnels hiding a secret history of New York were abandoned for mysterious reasons, and experts investigate why.

An eerie prison with a dark past that became the setting of an iconic Hollywood movie and alien monoliths on a strange and remote island are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.

An alien Stonehenge with a sinister purpose, an eerie building filled with strange labyrinths, and an endless concrete track in the middle of nowhere are deserted engineering projects, and new discoveries reveal why they were abandoned.

The world's strangest ghost towns are home to dark secrets, creepy buildings, and eerie sights, and new discoveries reveal why they were abandoned.

On a strange island off the coast of Croatia, the mysterious ruins of a long-abandoned hideout look like they once belonged to a James Bond supervillain, and new discoveries reveal why it was built and why they were abandoned.

The ruins of a once-palatial compound contain the secrets of one of history's most notorious criminals, and new discoveries reveal why this high-security estate was built and why it was abandoned.

Tunnels filled with human bones lie beneath the streets of Paris, and this horrifying engineering marvel points to a dark secret; new discoveries reveal why this grisly underground death maze was built and why it was abandoned.

A ghost town in the American West was once a Gold Rush hotspot and one of the most violent places in America. Today, there are legends of a secret treasure buried in the surrounding hills, and new discoveries might finally reveal its true location.

In Alaska, the ruins of a massive compound point to eerie evidence of an apocalyptic mystery. New discoveries reveal why this strange marvel was built in the snowy wilds of the Last Frontier and why it was abandoned.

A strange complex of tunnels on the grounds of a bizarre mansion were under lock-and-key for a century. Since its rediscovery, some believe its mysterious place is a gate to hell. New discoveries reveal its secret purpose and why it was abandoned.

Near the destroyed city of Pompeii, an eerie complex of underground tunnels snakes beneath a volcano, and some believe these passages were intended as a gateway to hell. New discoveries reveal exactly why they were built and why they were abandoned.

A strange complex of buildings on a remote tropical island was once home to a large seaside community, but today, locals avoid the area and claim that it's haunted. New discoveries reveal why this eerie place was built and why it was abandoned.

At an infamous prison in the Amazon, the most dangerous criminals on earth faced hard labor, a hostile environment, and death by guillotine; today, it's deserted, and new discoveries reveal why this hellish compound was built and why it was abandoned.

An abandoned town in the Nevada desert is the ruins of an American Atlantis, destroyed by catastrophic floods when the Hoover Dam was built; today, experts investigate the secrets of this eerie ghost town as water levels recede and the city reemerges.

A mysterious castle was once a fairytale estate, but today, the building is said to be haunted, and experts investigate the secrets of this eerie fortress and the ghostly stories inside.

A mysterious town in the hills of South Africa was once a booming community, but today, the eerie place is deserted; experts reveal the cataclysm that caused the people of this once-prosperous town to suddenly leave and never come back.

On a desolate island near Greece, abandoned buildings are evidence of a group of people that were forbidden to leave; experts reveal who was forced to stay here and if there was a cover-up to conceal what really happened at this strange place.

A vast network of subterranean bunkers in the American West was home to the power to destroy nations. But today, this facility is deserted, and new discoveries reveal why this eerie place was built and why it was abandoned.

A haunted prison with a terrifying past once housed America's most notorious criminals. But today, the fortress stands in ruin, and experts reveal evidence of ghostly secrets hidden in the crumbling jailhouse walls.

An abandoned system of caves was once the meeting place of a secret society that worshiped Satan and performed black magic. New discoveries at this mysterious site reveal what really happened here and why a Founding Father was a frequent guest.

Special access to the world's strangest disaster zones reveals the buried secrets, eerie sightings, and long-lost treasures in ruined, apocalyptic hellscapes; new discoveries reveal why they were built and why they were abandoned.

In a remote Louisiana swamp, the ruins of a massive industrial operation suggest that something evil once happened here, and new discoveries at this eerie site reveal what these abandoned buildings were for and why they were deserted.

An abandoned industrial complex by Lake Michigan was once a top-secret military compound that protected America from enemy attacks; new discoveries reveal what really happened here and why the government turned its back on this juggernaut.

An island of dense jungle is home to an abandoned complex with a dark past of bloodshed and rebellion, and new discoveries at this deserted place reveal why it was built and the gruesome circumstances of its downfall.

A strange bunker near the Kennedy Space Center once served a top-secret military function should doomsday ever come to the Sunshine State; experts use declassified intel to reveal the sinister purpose of this forbidding facility and why it was abandoned.

An abandoned castle is the site of hundreds of horrific murders perpetrated by the mysterious countess who once lived there. She's alleged to be one of the most prolific killers in history. New discoveries reveal what happened here.

Abandoned towers in southern Greece are the ruins of a fearsome warrior civilization descended from the Spartans, and new discoveries reveal the role these towers played during generations of violent blood feuds among the clans that lived here.

A massive, alien-like fortress built into a mountainside is the central node to a network of pipelines that race outwards like tentacles; behind-the-scenes access reveals the secrets of why this strange complex was built and why it was abandoned.

The ruins of an abandoned prison are evidence of a chaotic riot that put the prisoners in charge; special access to its burnt-out interior reveals how inmates took over Ireland's Alcatraz and why it is deserted today.

An eerie set of buildings in Paris is evidence of an unspeakable evil; new discoveries reveal the horrific things that happened here, and why they were abandoned.

A strange bunker in a treacherous landscape once belonged to a notorious dictator who's paranoid fantasies drove bizarre and elaborate feats of engineering; new discoveries reveal the secrets of these structures and why the nightmares that built them.

An underground labyrinth once used by a secret police force could warp the mind and turn friend into foe; experts turn up new evidence pointing to madness, murder, and mayhem, revealing what happened in these cursed tunnels and why it was abandoned.

Deep in the wilderness of the American south, a long-abandoned amusement park is home to secrets of a forgotten, imaginary world. When experts investigate, they reveal why this bizarre place was built and what caused its downfall.

A Mediterranean island paradise is not all that it seems; its complex of abandoned buildings were once prisons for the world's most dangerous Mafiosi; experts investigate new evidence to reveal who was imprisoned here and the secrets they left behind.

Places that were once home to or inspired Hollywood films, world-famous musicians, a sports legion, and war heroes are now run-down, abandoned, and forbidden; experts investigate their mysteries and reveal the astonishing secrets behind ten of the world's most iconic abandoned places.

A deserted facility in the remote countryside features mysterious graffiti that may be highly advanced mathematical equations pointing to a dark secret; experts investigate this classified military wasteland with a deadly past. 

Ghostly remnants of a beautifully constructed town in the remote backwoods of Kentucky suggests a forgotten tale of utter catastrophe and devastation; experts investigate and uncover the dark and oppressive history of a deadly industrial mining complex. 

The haunting remnants of a settlement in the Nevada desert lie scattered with decaying machinery and remain trapped in a bizarre time-warp; experts uncover a forgotten mine where dreams of discovering a fortune were met with chaos and murder. A abandoned fortress on the cliffs of Malta that appears to be a prison at first glance mark the abandoned Fort Delimara. A abandoned facility that had the worlds tallest structure at the time of construction in Poland. A abandoned fortress that guarded the entrance to the Firth Of Fourth in Scotland during world war 1 and 2 is explored.

A complex of tall, windowless buildings in the American Rust Belt holds the secrets to a lost empire of industry and wealth; experts investigate these mysterious structures to reveal why this once powerful metropolis is now home to abandoned ruins.

A battle-scarred ruin in the Middle East is evidence of espionage that resulted in tremendous violence on a vast scale; experts expose the truth behind the strange building that holds the secrets of one of the world's most infamous deceptions.

Abandoned hangers and bunkers populate a bizarre facility in the middle of nowhere, but among them are other structures whose purpose are oddly obscured; experts investigate a highly-classified military cover-up with extraterrestrial objectives.

The ruins of a historic Scottish castle are now a bewitching wilderness of hidden dangers with deadly booby traps obscured afoot; experts and historians reveal a bygone Second World War military hospital with bizarre ties to an infamous Nazi occupant.

The world's abandoned structures hold new evidence about the lives and deeds of history's greatest heroes and villains, and using the latest discoveries at these mysterious sites, experts count down the ten most significant. 

A collection of ramshackle structures with a mystical facade lie mysteriously deserted on the tropical island of Bali; experts investigate and uncover the ruins of a bizarre amusement park complex with a disastrous past.

Long, dome-like structures camouflaged by a rural landscape conceal the remains of concrete vaults with a hidden history; experts investigate and uncover state-of-the-art bunkers built to conceal and protect a deadly nuclear secret. 

A strange sea fortress that guards icy waters is home to a grim secret; experts investigate the mysteries at this eerie structure, which fought an invisible enemy far more deadly than ever imagined.

A desert island adrift in the Gulf of Mexico contains a massive and marooned structure with a contagious past; experts investigate and uncover a desolate military fortress turned prison and plagued by a deadly disease.

A war-torn Italian ghost town immortalized by a legendary Hollywood director blurs the lines between fiction and reality; experts investigate and uncover a forgotten landscape of ruins captured in a WWII documentary. 

The ruins of a dreamlike Polish palace hide an astonishingly dark history that's shrouded in mystery to this day; experts investigate and uncover an ornate gothic structure that concealed a nightmare of Nazi experimentation. 

A breathtaking stainless steel tower seems otherworldly and out of place in the remote mountain forests of Croatia; experts investigate and uncover a dark past of Nazi-led conflict and a monument to a desperate fight for survival. 

A derelict beachside resort along the Black Sea is constructed upon deception and deep connections to the criminal underworld; experts investigate and uncover dark secrets behind a sprawling holiday complex constructed by the Russian mafia.

The haunting remains of an isolated ghost town high in the Colorado mountains suggest a once booming mining community left in devastation; experts uncover an inhospitable land of shattered dreams where fortune seekers chased the American dream. 

An enormous concrete box with bizarre circular openings looms on the coast of an island near mainland China; Experts investigate and uncover tunnels leading to an enormous underground complex that nearly triggered a nuclear war.

The bizarre remnants of a housing complex lie mysteriously deserted in the Ohio industrial town of Campbell. Experts investigate and uncover the dark, turbulent past of the oppressive steel firm Youngstown Sheet & Tube Company and the labor strikes that resulted in deadly riots in 1916.

An enormous war machine, the  KM (Korabl Maket), known colloquially as the Caspian Sea Monster, lies stranded in a coastal grave along the beaches of Dagestan, Russia; experts investigate and uncover the ruins of an experimental Soviet ground-effect vehicle designed to strike fear in Western governments during the Cold War.

A looming skyscraper, Ponte City, once an exclusive residential complex, turns into a dystopian ruin in Johannesburg, South Africa; experts investigate and uncover a symbolic structure of urban decay under the shameful shadow of apartheid.

Experts investigate how a ruinous financial crisis combined with murder mystery schemes caused the decline of the Sathorn Unique Tower, an opulent skyscraper in the heart of Bangkok's busy streets, a structure now little more than an empty shell.

A majestic vacation estate for the rich and powerful now lies abandoned in the highlands of Argentina - the Hotel Edén in Córdoba Province. Experts investigate and uncover a once struggling hotel transformed into a luxurious resort outpost for elite Nazi German sympathizers. 

The sprawling ruins of a once lavish destination are now mysteriously deserted in the mountains of Romania. Experts investigate and uncover the remains of the Herculane Spa, a luxurious spa resort and royal retreat entangled in a web of corruption.

The ruins of a coastal fortress sit atop a jagged outcrop along the beaches of Wales - St Catherine's Fort and Island in Pembrokeshire. Experts investigate and uncover a derelict 19th-century British fortification that housed a series of occupants, including an exotic, private zoo.

A cluster of military defensive structures among a quaint holiday village lies deserted on a San Francisco Bay island; experts investigate and uncover a mysterious Civil War outpost on Angel Island that conceals a dark and hellish history.

An eerie ghost village in west-central France, Oradour-sur-Glane, appears as if it were mysteriously abandoned and destroyed all at once; experts investigate and uncover the remains of a derelict settlement left as a memorial to a murderous WWII Nazi raid.

An opulent chateau perched in the middle of a lake, the Château de la Mothe-Chandeniers, now stands dilapidated in the Loire Valley of France. Experts investigate and uncover the remains of a festering palace whose owner was labeled a traitor by France's most notorious king.

A research complex housing two enormous satellites is now mysteriously derelict in the rural expanse of Woodbury, Ga.; experts investigate and uncover the Woodbury Research Facility, where planetary scientists explored possible evidence of extraterrestrial intelligence.

The ruins of a mental health institution, Hartwood Hospital in North Lanarkshire, lie deserted in the Scottish woodlands; experts investigate and uncover the terrifying past of a notorious psychiatric asylum where many entered, but few escaped.

The remnants of a desolate ghost town with a violent past, Agdam, lie in the shadow of the Caucasus Mountains in Azerbaijan; experts investigate and uncover a destructive ethnic and territorial conflict, the Nagorno-Karabakh Conflict, that forced the evacuation of the entire city.

A forgotten military fortification connected to a network of secret tunnels are mysteriously hidden within the Rock of Gibraltar; experts investigate and uncover a derelict war-torn complex constructed for a highly classified WWII spy operation.

The remains of a derelict industrial complex connected to a mysterious water canal lie deserted in the Florida Everglades; experts investigate the Aerojet Dade Rocket Facility, an abandoned solid-fuel rocket testing facility critical to humanity's race to the stars.

A series of dark, subterranean vaults lie hidden beneath the bustling streets of Edinburgh, Scotland; experts investigate and uncover a vast network of tunnels and chambers that contain a history of opportunity, crime, and destitution.

The Variety Theater, a once-majestic theater hosting entertainment for generations in lavish surroundings, now lies mysteriously derelict in Cleveland, Ohio. Experts investigate a record-breaking heavy metal concert performed by Motorhead on December 2, 1984, that would spell the theater's eventual downfall. With a sound level of 130 decibels, this was the loudest rock performance ever recorded. 

The bizarre remains of an Old West mining town lie mysteriously deserted high in the mountains of Maggie Valley, North Carolina; experts investigate and discover an abandoned ghost town theme park that some local residents believe carries a curse.

Houska Castle, an eerie castle with a supernatural attraction, stands derelict in the dense forests near Doksy in the Czech Republic; experts investigate and uncover legends of a concealed gateway to hell and links to horrific Nazi Germany occult experimentation.

Varosha, an entire city district of desolate streets and derelict buildings in Famagusta, lies mysteriously untouched for decades in Eastern Cyprus; experts investigate and uncover a once opulent resort town suddenly entangled in the 1974 Turkish military invasion, Operation Atilla.

A legendary U.S. Naval war vessel, the USS Hornet (CVS-12), now stands as a monument to space exploration in Alameda, California; experts reveal how the formidable WWII aircraft carrier served a vital role in historic Apollo spaceflight recovery missions.

A disintegrating tower, once a thriving cultural hub, now stands hollow and derelict in Monrovia, Liberia; experts investigate and uncover a landmark skyscraper left to decay in the wake of a bloody political coup.

In 1972, the porn baron Bob Guccione, founder of Penthouse magazine, established the Haludovo Palace Hotel on the Croatian island Krk north of Malinska. The resort was a hedonistic paradise to avert nuclear catastrophe - attracting rich and infamous clients in the process, like Saddam Hussein.

587 half-built castles near Mudurnu, Turkey, stand as a whimsical reminder of a residential development that was supposed to feature thermal baths and panoramic views. The ambitious Burj Al Babas project ended abruptly in 2019 when the Sarot Group construction company faced financial difficulties.

Famous Beatles producer George Martin envisioned this Caribbean mecca for rock legends. AIR Studios Montserrat opened in 1979, and many legendary records were created there. The studio had to close after a series of natural disasters rocked the small island of Montserrat.

This Seoul amusement park is full of rusted-out rides and unfinished renovations. Forced to close due to financial problems, the park has found a second life after being used as the setting of K-pop album covers and music videos.

In a California desert, a once glittering Hollywood hotspot, the Byron Hot Springs Hotel, gets converted during World War II into a top-secret interrogation center for high-value German and Japanese POWs. Before being shuttered, this high-tech facility called Camp Tracy gathered reams of valuable wartime intelligence.

Formerly known as one of the toughest prisons in America, this massive complex was once home to medical experiments and a chaotic hostage situation; it's better remembered as the setting for the iconic opening scene of "The Blues Brothers."

Graffiti scratched into the walls of a military base on the British coast sheds light on a secret raid against the Nazis; the story left behind by the soldiers does not match the rosy picture that was painted by the media...

In the Turkish capital of Ankara, an ambitious new theme park (Wonderland) is plagued by budget problems, mechanical issues, and political conflicts before ultimately being shuttered. Decaying rides and old dinosaurs stand as symbols of excess on the city skyline.

Conspiracies swirl around an abandoned military base in Long Island, where it's alleged that covert government experiments took place underground. Experts discuss the critical role that the base played in defending America's coastline by both air and sea.

In modern-day Turkey, on the coast of the Aegean Sea, archaeologists discovered hilltop ruins that are believed to be the site of one of the world's most enduring stories -- the legend of Troy and the Trojan Horse...

On a picturesque island off the coast of Brazil, this penal colony was once the site of a dramatic prisoner uprising; among the ruins lies the story of the violent rebellion and the recapturing of the island by military forces...

This decaying fortress once stood between the Ancient Roman and Persian Empires; though the stronghold's location attracted great wealth, it also attracted attention from unfriendly neighbors...

In 1920, a teenage girl in Japanese-occupied Korea is martyred in prison and becomes a national hero. Seodaemun Prison, the facility in Seoul that held Yu Gwan-sun, stands in remembrance of her bravery and the Korean struggle for independence.

Notorious gunslinger John Dillinger once made a daring escape from this unassuming Lake County Jail in Crown Point, Indiana, in 1934. Today, the story of his clash with Sheriff Lillian Holley, Indiana's first female sheriff, and his dramatic getaway continues to fascinate the public.

A building in Colorado is still marked with bullet holes from a Wild West shootout between union members and state militia; the ruins of the old mining town tell the heated story of a labor dispute that ended in sabotage and murder.

In the former Soviet Union, this theater and others like it were used to influence the minds of the masses; though its grand auditorium is now empty, the building still serves as a testament to the power of cinema...

Some of the world's most incredible engineering projects now lie in ruins. Some of the world's most incredible engineering projects now lie in ruins. These deserted places are home to extraordinary mysteries and untold secrets, and we revisit them to understand how they were built, and why they were abandoned.

Go inside the abandoned city of Chernobyl to follow an investigation into the truth behind the nuclear meltdown there over 30 years ago. New evidence reveals that this accident may be one of the greatest sabotages in history.

Uncover the secrets of Nazi engineering projects that now lie in ruins. These deserted places are home to extraordinary mysteries and untold secrets, and are revisited to understand how they were built, and why they were abandoned.

This episode is a compilation of segments from S01E01, "Nazi Ghost Town", S01E05, "Soviet Doomsday Device", and S01E04, "Wild West Apocalypse".

Uncovering the secrets of Soviet engineering projects that now lie in ruins; these deserted places are home to extraordinary mysteries and untold secrets, and we revisit them to understand how they were built, and why they were abandoned.

This episode is a compilation of segments from S01E03, "Phantoms Of Chernobyl", S01E01, "Nazi Ghost Town", and S01E05, "Soviet Doomsday Device".

Uncovering the secrets of American engineering projects that now lie in ruins; deserted places play home to extraordinary mysteries and untold secrets; revisiting them to understand how they were built and why they were abandoned.

This episode is a compilation of segments from S01E01, "Nazi Ghost Town", S01E06, "The Tesla Conspiracy", and S01E03, "Phantoms Of Chernobyl".

Uncovering the secrets of military engineering projects that now lie in ruins; these deserted places play home to extraordinary mysteries and untold secrets; revisiting them to understand how they were built and why they were abandoned.

This episode is a compilation of segments from S01E02, "Curse Of Hell Island", S01E03, "Phantoms Of Chernobyl", S01E04, "Wild West Apocalypse".

America is the home to strange and incredible engineering projects that now lie in ruins, and new discoveries reveal how they were built and why they were suddenly abandoned. There are cities that are now empty ghost towns, bridges that were never finished, and roads to nowhere. This episode is a mashup of segments from S01E01, "Nazi Ghost Town", S01E06, "The Tesla Conspiracy", and S01E03, "Phantoms Of Chernobyl".

New discoveries reveal why the world's most ambitious engineering projects were abandoned, unraveling the dark mysteries and bloody secrets of these strange ruins. This episode is a mashup of S02E06, ''Secrets of the Alien Shrine" and S02E08, "Sea Fortress of Doom''.

The world's most mysterious abandoned places are home to dark secrets, and now, new discoveries at these strange sites reveal the untold stories of why they were abandoned. This episode is a mashup of S03E02, "Nightmare on Blood Mountain" and S03E05, "America's Doomsday Town".

The world's most mysterious abandoned places are home to dark secrets, and now, new discoveries at these strange sites reveal the untold stories of why they were abandoned. This episode is a mashup of S03E06, "City of the Damned" and S03E04, "Underwater Ghost Prison".

The world's most mysterious abandoned places are home to dark secrets, and now, new discoveries at these strange sites reveal the untold stories of why they were abandoned. This episode is a mashup of S03E03, "Tower of Death" and S03E07, "The Town That Disappeared".

The world's most mysterious abandoned places are home to dark secrets, and now, new discoveries at these strange sites reveal the untold stories of why they were abandoned. This episode is a mashup of S02E03, "Arctic Hell Pit" and S03E08, "Nazi Death Star".

The world's most mysterious abandoned places are home to dark secrets, and now, new discoveries at these strange sites reveal the untold stories of why they were abandoned. This episode is a mashup of S02E08, "Sea Fortress of Doom" and S03E09, "The Real Shawshank".

Some of the world's most incredible engineering projects now lie in ruins; cities that are now empty ghost towns, bridges that were never finished and roads to nowhere; these deserted places are home to extraordinary mysteries and untold secrets.

New discoveries reveal why the world's most ambitious engineering projects were abandoned, unraveling the dark mysteries and bloody secrets of these strange ruins.

This episode is 2-hour a mashup of S04E07, "Alien Hell Portal", and S04E04, "Labyrinth of the Dead".

The United States is home to countless eerie and abandoned places; and using the latest tech, experts make new discoveries to reveal the secrets of how they were built and why they were abandoned. The segments of this special come from various episodes.

The Soviet Union built countless engineering marvels beyond the Iron Curtain, but today, these mysterious places are abandoned; experts use cutting-edge tech to reveal the secrets of how they were built and why they were abandoned. The segments of this special come from various episodes.

The Nazis built secret megastructures during their bloodthirsty quest for world domination, but today, they're now abandoned; experts are rediscovering these lost places to reveal the mysteries of how they were built and why they were deserted. The segments of this special come from various episodes.

Many of the world's most mysterious abandoned buildings are hidden underwater and underground. But now, experts use cutting-edge tech to reveal the secrets of these strange places and finally explain why they were deserted. The segments of this special come from various episodes.

A village on a remote island was once home to the victims of deadly disease, but today, the island and its buildings are abandoned; experts investigate what went wrong in this strange place and what happened to the people who once lived here. The segments of this special come from various episodes.

The ruins of a great wall that once marked the edge of the world hold the secrets of the ancient soldiers who stood watch here long ago; new discoveries reveal who the wall was meant to keep out and why the site is littered with skulls. This episode is a mashup of S06E03 "End Times on Lake Michigan" and S05E02 "American Atlantis."

Human bones line a sprawling maze of tunnels beneath the streets of Paris, and this gruesome labyrinth is evidence of a devastating horror; new discoveries reveal the secrets of this strange place and why it was abandoned. This episode is a mashup of S06E04 "Hell on Blood Island" and S04E04 "Labyrinth Of The Dead."

The site of strange, alien-like structures hidden deep within a remote forest was once one of the deadliest places in the world, and new evidence reveals who built these bizarre ruins and why. This is a mashup of S06E05 "Florida Doomsday Castle" and S04E09 "Haunting on Plague Island."

An abandoned airplane hangar in Ukraine was once home to the jewels of the Soviet Union's aeronautics industry, and inside, experts reveal new evidence about its top-secret space shuttle program; these fresh discoveries uncover what really happened here. This episode is a mashup of S06E07 "Towers of Blood" and S06E06 "The Killer in the Castle."

Some of the world's most nightmarish places are abandoned buildings and failed engineering projects; and using cutting-edge tech, experts make new discoveries to reveal the secrets of how they were built and why they were abandoned. This two-hour episode uses segments from various past episodes with cold weather as a common trait.

From secluded islands to cities perched along cliffs, abandoned structures, and failed engineering projects can be found in the world's most remote locations; using cutting-edge tech, experts reveal how they were built and why they were abandoned. This two-hour episode uses segments from various past episodes.

Underground bunkers and subterranean labyrinths entomb dark secrets of the past waiting to be discovered; experts investigate the mysteries of these astonishing feats of engineering to uncover how they were constructed and why they were abandoned.

A deserted amusement park and ruins of a top-secret military doomsday bunker hold secrets to a strange and forgotten past; experts investigate these remarkable feats of engineering to uncover how they were constructed and why they were abandoned.

A Mediterranean island paradise and a once-thriving South African community are now all mysteriously deserted and desolate landscapes; experts investigate the secrets of these remarkable places to uncover how they were built and why they were abandoned. This episode is a mashup of S07E03 "Secrets of Mafia Island," S05E03 "Haunting of Heartbreak Castle," and S05E04 "Kingdom of the Vanished."

Forgotten places once home to Hollywood films and a terrifying prison fortress are now neglected and haunted ruins; experts investigate their mysteries and reveal the remarkable secrets behind the most iconic and ghostly places. This episode is a mashup of S07E04 "The World's Greatest Icons" and S05E07 "The Devil's Prison."

An infamous prison in the Amazon and a deserted military facility in the remote English countryside contain a haunting and deadly past; experts investigate the secrets of these remarkable places to uncover how they were built and why they were abandoned. This episode is a mashup of S07E05 "Factory of Death," S05E01 "Jungle of the Damned," and S03E07 "The Town That Disappeared."

A desolate fortress in a secluded mountainside and the remnants of a town in the backwoods of Kentucky are now ghostly ruins; experts investigate the secrets of these remote, rural mysteries to uncover how they were built and why they were abandoned. This episode is a mashup of S07E06 "Ghosts of Black Mountain," S06E08 "The Thing of Hell Mountain," and S04E09 "Haunting on Plague Island."

The decaying remains of a lost military base and the haunting remnants of a forgotten Nevada settlement are now barren wastelands; experts investigate the secrets behind these desert landscapes to uncover how they were built and why they were abandoned. This episode is a mashup of S07E07 "The Doom of El Dorado," S05E05 "Journey to Outcast Island," and S02E03 "Arctic Hell Pit."

A forgotten city in the cliffs of Colorado and a desolate complex of windowless buildings in the Rust Belt now stand in ruins; experts investigate the secrets of these deserted American mysteries to uncover how they were built and why they were abandoned. This episode is a mashup of S07E08 "Ruins of the Rust Belt," S05E06 "Secrets of the Doomsday Caves," and S04E07 "Alien Hell Portal."

The desolate fortress of history's most infamous drug lord and a battle-scarred ruin in the Middle East contain a violent past; experts investigate the secrets of these mysterious compounds to uncover how they were built and why they were abandoned. This episode is a mashup of S07E09 "Fortress of the Spy," S04E08 "Pompeii's Gate to Hell," and S04E03 "Escobar's Castle."

The remnants of a classified military wasteland and the ghostly remains of a remote Kentucky mining town are now forgotten ruins; experts investigate the secrets of these secluded facilities to uncover how they were built and why they were abandoned. This episode is a mashup of S07E05 "Factory of Death" and S07E06 "Ghosts of Black Mountain."

The ruins of a mysterious hideout in Croatia and the decaying remains of Ireland's Alcatraz contain a haunting past; experts investigate the secrets behind these deserted island structures to uncover how they were built and why they were abandoned. This episode is a mashup of S07E10 "Mystery of the Alien Base," S04E02 "Secrets of Supervillain Island," and S06E09 "Anarchy on Ireland's Alcatraz." 

The remains of a Scottish castle adapted into a WWII hospital and a classified complex on Lake Michigan are now forgotten ruins; experts investigate the secrets of these military facilities to uncover how they were built and why they were abandoned. This episode is a mashup of S07E11 "Ghosts of the Cursed Castle," S06E03 "End Times on Lake Michigan," and S06E07 "Towers of Blood."

A strange Soviet monolith, known as the Tower of Death, and a bizarre bunker constructed by a violent dictator are now forgotten ruins; experts investigate the secrets of these haunting structures to uncover how they were built and why they were abandoned. This episode is a mashup of S06E11 "Nightmare at Fort Paranoia," S04E05 "Treasure of Outlaw Valley," and S03E03 "Tower of Death."

Evidence of an unspeakable evil in a set of Parisian buildings and an alien Stonehenge with a sinister purpose are now abandoned ruins; experts investigate the secrets of these dark structures to uncover how they were built and why they were abandoned. This episode is a mashup of S06E10 "House of Horror," S02E08 "Sea Fortress of Doom," and S03E10 "Secrets of Alien Stonehenge." 

An abandoned island complex and a haunted prison fortress contain a dark and terrifying past of bloodshed; experts investigate the violent secrets behind these ghostly structures to uncover how they were built and why they were abandoned. This episode is a mashup of S06E04 "Hell on Blood Island," S03E02 "Nightmare on Blood Mountain," and S05E07 "The Devil's Prison."

A network of tunnels hiding a secret history of New York and a South African ghost town are now mysteriously abandoned ruins; experts investigate the cryptic secrets of these deserted places to uncover how they were built and why they were abandoned. This is a mashup of S05E04 "Kingdom of the Vanished," S03E08 "Nazi Death Star," and S03E01 "Doomsday at Dragon's Teeth."

Desolate structures left in ghostly ruins are scattered across the US, and each holds a story waiting to be discovered; experts use cutting-edge tech to investigate these forgotten places and reveal how they were built and why they were abandoned. The segments of this special come from various episodes. 

The haunting remnants of a backwoods Kentucky town and a deserted Spanish village with a bloody past are now abandoned ruins; experts investigate the mysteries of these deserted cities to uncover how they were built and why they were abandoned. This is a mashup of S03E06 "City of the Damned," S03E05 "America's Doomsday Town," and S07E06 "Ghosts of Black Mountain."

Tunnels filled with human bones beneath the streets of Paris and ruins of a massive industrial operation contain a haunting past; experts investigate the evil secrets behind these deserted places to uncover how they were built and why they were abandoned. This is a mashup of S06E02 "Swamp of Despair," S04E04 "Labyrinth of the Dead," and S07E02 "American Ghost Park."

An infamous prison in the Amazon jungle and an underground labyrinth used by a secret police force contain a murderous past; experts investigate the secrets behind these hellish structures to uncover how they were built and why they were abandoned. This is a mashup of S05E06 "Secrets of the Doomsday Caves," S07E01 "Into the Murder Labyrinth," and S05E01 "Jungle of the Damned." 

An island paradise home to a desolate prison and an abandoned system of caves for a secret society contain a haunting past; experts investigate the evil secrets behind these deserted places to uncover how they were built and why they were abandoned. This is a mashup of S05E08 "Curse of Satan's Catacombs," S07E03 "Secrets of Mafia Island," and S01E02 "Curse of Hell Island." 

America's Wild West is home to abandoned ruins that attest to the strange, dark, and mysterious things that once happened here; experts investigate the secrets behind these desolate places to uncover how they were built and why they were abandoned. The segments of this special come from various episodes.  

Abandoned towers of a fearsome warrior civilization and a castle that was once a fairy-tale estate are now haunted ruins; experts investigate the secrets behind these desolate fortresses to uncover how they were built and why they were abandoned. This is a mashup of S05E03 "Haunting of Heartbreak Castle," S06E07 "Towers of Blood," and S07E05 "Factory of Death."