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

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

Water of undetermined depth has attracted rare fish and cult leaders alike.

This semi-hidden Manhattan restaurant is based out of a loading dock.

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

Over the dunes of the Empty Quarter, the mysterious music of the desert.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

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

The world's highest and most dangerous infinity pool lies at the precipice of Victoria Falls.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

The hallucinogenic center of the ancient world.

A spectacular cave and a beguiling lake.

A semi-scholarly approach to sex.

The former hotel where Tesla invented the radio.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

An enormous, 30-story-deep hole in the middle of Guatemala City.

A subterranean Holocaust refuge within one of the world's longest cave systems.

One of the world's southernmost bars.

The world's first and only natural nuclear reactor.

The subtle interplay of fire and water is hard to ignore at this remote Jamaican spring.

A city continually buried under the ash of a volcano that has been erupting for more than 15 years.