This massive underground salt mine now holds a sci-fi theme park in its depths.

These circular ruins are all that remain of a 17th-century Arctic whaling outpost.

This taxidermy scene brings the struggle for survival in the Indian jungle to a quiet corner of a Manhattan museum.

The tiny, studious rodents greet visitors to the National Archives of Finland.

This art installation at an abandoned lipstick factory has distinct anti-capitalist vibes.

Dine amidst exotic plants at this former royal greenhouse.

You can swim in these highly salty, mesmerizingly blue lakes in the Atacama Desert.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

This former fascist summer camp was abandoned for decades.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

The abandoned ruins of a failed resort hide on this verdant, picture-perfect island.

The city of Palestrina was built around this magnificent terraced sanctuary dedicated to the pagan goddess Fortuna.

A dilapidated psychiatric facility on the outskirts of Milan where electroconvulsive therapy was developed and Napoleon once lived.

The highest waterfall in Italy is only "turned on" five times a year.

142 ceramic steps become a mosaic once a year.

An open-air museum in a mountain valley features works designed to blend in with—and disintegrate back into—their natural surroundings.

The top of society once luxuriated in this world-class hotel, which continues to impress, even in ruin.

Artist Diego Morlin's war between the natural and human worlds is a wanderer's delight.

This entire town moved to a safe location after it was devastated by an earthquake, but the remains of the original town are still around.

Crumbling ruins of the thermal baths that once attracted royals and aristocrats from throughout Europe.

These delicate sand pyramids look like naturally occurring gothic spires.

A domed disco abandoned since the '70s now attracts artists and explorers under its unique roof.