Season 4 - Episode Guide

Don Wildman explores deep below ancient ruins as he searches for clues pointing to the true fate of the once-mighty Mayan empire.

Don explores top-secret military and government tunnels and looks into classified technology that could be used to build entire cities right under our feet. He tours a Titan II missile site near Green Valley, Arizona; roams outside Area 51 and Nellis Air Force Base, Nevada; explores a tunnel boring machine (TBM) at the Three Rivers Tunnel Project near Fort Wayne, Indiana; examines the potential for nuclear-powered tunnel boring; tours the former emergency relocation bunker for the United States Congress under West Virginia's Greenbrier Resort; and investigates U.S. Army underground urban warfare training in Indiana.

Don uses brand-new mapping technology to expose the dark and deadly uncharted spaces beneath American cities. He explores the criminal underworld below Portland, Oregon; Seattle, Washington; Chicago, Illinois; and Los Angeles, California.

Don goes deep beneath the Great Lakes and explores flooded caves as he searches for evidence of a mysterious, cave-dwelling, pre-Clovis society that may have been the first people to reach America. Evidence presented: a mastodon image carved on a rock beneath Lake Michigan, 16,000-year-old poop and arrowheads from a dry cave in Central Oregon, and a 13,700-year-old human female skeleton from Cenote Naharon in Mexico's Yucatan. Nicknamed Eve of Naharon, she is the oldest human skeleton found in the Americas.

Don explores newly discovered ruins, caves, and shipwrecks in Croatia and Montenegro as he uncovers the true story of Queen Teuta of Illyria, a formidable queen who dared to defy the mighty Roman Republic in the 3rd century BC.

Don goes deep beneath Bagras Castle, a Knights Templar stronghold in Turkey, to explore a provocative theory that may link the fabled secret society to Freemasonry and America's founding fathers. He also explores the Old North Church in Boston, Massachusetts and Fort Mifflin in Pennsylvania.

Don explores the massive underground cities of Cappadocia in the mountains of Turkey that may have been home to the first civilization on Earth. Also explored are Göbekli Tepe. 

Don follows the clues hidden underground as he searches for evidence of 10,000 Aztecs who fled Mexico with Montezuma's treasure and disappeared somewhere in America, perhaps returning to their ancestral home, Aztlán.