Volcanically heated hot springs.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

A market for witches is hidden within a train station.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

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

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Record-holding coffin moonlights as an eatery run by undertakers.

The last planned Soviet city was built for the former residents of Pripyat after the Chernobyl disaster.

It's the only museum of its kind in Ukraine.

Ukraine's oldest operating pharmacy now offers guests a fascinating walk through apothecary history.

The Vatican's secret porn-festooned bathroom was painted in erotic murals by one of the greatest artists of the Renaissance.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

This unassuming museum's slogan translates to “there is a limit of sadness, anxiety has no limits."

This attraction was abandoned after the Chernobyl disaster.

The largest catacomb system in the world.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

A trove of ridiculously valuable prints and manuscripts under one roof.

The immortal Hollywood star rests in peace in an unassuming Swiss village cemetery.

This colossal couch is an unlikely monument to Europe's first female Doctor of Law.

This early 19th-century graveyard is the final resting place of Vincent van Gogh's mother.

A giant floating rubber duck-bunny painted with a different design every year.