Ruins of the elaborate house where the enigmatic costume designer threw glamorous parties for New York's theatrical elite.

Part of one of the largest flooded cavities on the planet, and littered with prehistoric animal bones.

The center of the only hemisphere that awards visitors with a commemorative coin.

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

An emerald-green grotto just a short trip from Austin.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Forgotten German bunkers in China create a sharp cultural contrast.

Site of the largest impact event to occur over land in Earth's recorded history.

An abandoned relic of the city's failed experiment with below ground transit.

Island, once a pirate hideout, now home to an abandoned resort.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Rising from the sea like a stone monster.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

A remarkably intact castle that once was the largest in Ireland.

Northern Ireland's Brobdingnagian stepping stones.

These picturesque ruins crumble beautifully into the ocean.

The vast, legendary catacombs hold secrets much stranger than stacked bones.