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".

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 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".

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.

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".

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.

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".

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.

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".

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 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.

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.

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.

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.

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.