A flooded Mexican cave that hides a river beneath the water.

Home to an endangered salamander, a full moon celebration, and a large spring-fed outdoor swimming pool.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

One part antique store, one part curiosities hodge-podge.

An abandoned train station in Munich constructed for the 1972 Olympic games.

Along the most northwestern point in Africa is an ancient cave surrounded by legends.

The world's most famous donkey lives in this pen.

Guarded by the Angel of Grief, the Stanford family tomb attracts an odd mix of halloween revelry and somber contemplation.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

Major tourist destination known for its bubbling mud-pools and hot thermal springs.

The glacier tucked within a New Zealand rainforest.

This strange geological landscape erupts with sudden bursts of water.

A perfect turquoise lake colored with glacier dust.

Dolphins, ancient clams and hundreds of waterfalls make this one of the world's top tourist destinations.

The real life Hobbiton, this sheep farm has been forever transformed since being built for The Hobbit film series.

Tubing through a cave lit with glowworms is a magical underground experience.

This Bangkok high-rise looks like a rudimentary LEGO elephant.

This underground transport hub doubles as an art gallery.

Marvel at the excessive luxury of the ousted Ukrainian president's former estate.

This exquisite, alienesque piece of Soviet architecture is being threatened by modern shopping malls.

When you've got to go, you've got to go.

The deepest metro station in the world.

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