Siberian ghost town built by gulag prisoners.

Abandoned castle was once a grand example of Russian privilege, built exclusively to win a frivolous bet between noblemen.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

The dome-shaped reservoir of this old water tower produces unique acoustic effects.

No one knows who built this strange cave of worship or exactly why.

A Romanian church built from one single oak.

This Romanian village may have been drowned, but it is long from forgotten.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

An enormous concrete structure built over a nuclear crater.

The remains of one of America's first radiation testing grounds still rest ominously in a Georgia forest.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

From overly ambitious (and eventually abandoned) atomic dream to bustling office park.

Popular tourist destination where witches in dark hats sell dried llama fetuses for good luck.

This shell of a historic manor house on the Isle of Wight is said to be the most haunted site on the island.

An Italian hillside ghost town.

Cursed swimming pool left abandoned is now a favorite of filmmakers and ghost hunters.

Once the nail factory shut its doors, this Swedish factory town was abandoned, leaving behind a modern ghost town.

The post-apocalyptic remnants of a bucolic town ruined by a plane crash.

A former utopian healing center created by a huckster and built by derelicts.

The ghostly remains of an accidental sea.

The ghost town that ended up on Ebay.

One of the ghostly stops along Route 66.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.