At an infamous prison in the Amazon, dangerous criminals 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 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; experts investigate the secrets of this eerie ghost town as water levels recede and the city reemerges.

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

A one-time fairytale castle is rumored to be haunted; experts investigate the secrets and ghostly stories of this eerie fortress.

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.

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.

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 mysterious town in South Africa is deserted, even though it was once a booming community; experts reveal the cataclysm that caused the people of this once-prosperous town to suddenly leave and never come back.