Season 4 - Episode Guide

A cutting-edge investigation into the sinking of the Titanic reveals new discoveries that might finally explain the mysteries of her last moments, and experts get closer to a shocking secret: if there was a way to save almost everyone on board.

Egypt's strange Bent Pyramid is one of the world's most mysterious, ancient mega-structures, and new discoveries help experts investigate its dark secret: if it was always intended to look so bizarre, or if something went catastrophically wrong.

New discoveries at Pompeii's last unexplored area reveal the dark secrets of the doomsday event that destroyed it, and recently unearthed mummies might help answer Pompeii's most enduring mystery: why it was built on an active volcano.

For the first time, archaeologists use cutting-edge technology to discover what lies beneath China's Forbidden City, revealing the dark secrets of this mysterious mega-palace that have been buried for nearly 600 years.

The Inca capital of Cusco was said to be the site of untold gold and riches, and new discoveries at this mysterious site reveal the secrets behind this mighty empire's fall.

A ground-breaking experiment reveals how ancient Egyptians built the giant obelisks of Thebes and new discoveries at this holy site could explain why these mysterious marvels triggered the downfall of the pharaohs and the end of Egypt's golden age.

The discovery of strange giant stone heads in the Mexican jungle leads archaeologists to La Venta, the lost capital city of the Olmec, and new investigations real evidence that the secret knowledge of these mysterious people changed life in the Americas forever.

The treasures of Ramses II are found at Abu Simbel, a giant temple carved into a desert cliff over 3,000 years ago, and new discoveries at this marvel reveal the secrets of ancient Egypt's greatest pharaoh.

Deep in the jungle, the lost city of Tikal holds the dark secrets of the Maya, and now, a new investigation uncovers how it grew into a megacity home to 100,000 people, and why it was mysteriously abandoned.

New discoveries at a strange prehistoric site reveal the dark secrets and rituals of the mysterious people who built the world's largest stone circle, Avebury in England, three times bigger than Stonehenge, and just as enigmatic.

New evidence might reveal the dark secrets of a mysterious lost city, Thebes, that was one of the most important places of ancient Egypt until an apocalyptic event changed everything. This is a mashup of S02E09 "Mystery of Egypt's Mega Temple", S04E06 "Egypt's Lost Skyscrapers", and S03E03 "Forbidden City of the Pharaohs".

New discoveries at Pompeii are challenging everything we know about the apocalyptic volcanic eruption that destroyed it, and using cutting-edge tech, a team of experts is bringing this lost world back to life to reveal Pompeii's dark and deadly secrets. This is a mashup of episodes from two Science Channel series: "Secrets of the Lost" S01E03 "Pompeii: The Deadly Mystery" and "Unearthed" S04E03 "Pompeii's Doomsday Mummies".

New discoveries at lost Maya Ruins uncover the dark secrets of their civilization, revealing how bloody human sacrifice formed the basis of a mysterious people that met an apocalyptic end. This episode is a mashup of S01E01, "Mayan City of Blood" and S04E09, "Lost City of the Maya".

New discoveries at mysterious Inca sites believed to be the home of legendary treasures reveal something darker: mummies that hold the secrets to this mighty civilization's fall. This episode is a mashup of S02E07, "Hidden City of the Incas" and S04E05, "Inca Apocalypse: the Dark Evidence."