The ruins of an Estonian prison are drowning in the quarry lake where the convicts were once forced to work.

Steepest flood safety railway in the entire world.

The mortal remains of a Russian prince, priest and paranormal investigator who came to America in 1792.

Collection of trolley cars in the woods represent one man's attempt to preserve transportation history.

The ruined remains of a coal mining ghost town are hidden within the woods.

The eerie ruins of a remote abandoned hamlet said to be founded by the survivors of a shipwreck.

This off-the-beaten-path abandoned town is a relic of Montana's silver mining boom.

A little-visited ghost town state park offers a glimpse into Montana’s "Silver Queen."

Dig for your own trilobites in this goldmine of invertebrates.

A museum in rural Utah documents the history of the Japanese Americans who were forcibly relocated there.

This magnificent abandoned hotel has long been haunted by its Nazi past.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

The only Florida state park with publicly accessible caves.

Hideout of thieves, monks, and goat-footed gods.

The abandoned summer estate of the former Greek Royal Family.

An underwater statue of Christ blesses the depths off Key Largo.

An underwater city for the dead.

Two rocks in a perpetual kiss and one of "the most romantic spot in America."

An abandoned boat that's been stranded mysteriously for decades.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

The construction of a tram line unveiled hidden remnants of the old medieval city.