This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This abandoned Slovenian military barracks has become a punky-political art squat.

A whimsical bridge adorned with decorative dragons.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

Where the lovelorn find a home for their sentimental keepsakes.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

The topiary maze at the Habsburg hunting lodge.

Baroque celebration of the end of the Great Plague of Vienna.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

The prototype for all Nazi concentration camps.

Go surfing on this urban wave, "hacked" by local surfers.

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

Medicinal spa created with the discharge from a geothermal energy plant.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

Three columns of volcanic rock shoot out of the ocean.