This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

This cubist Vienna church building looks like some sort of alien stonehenge.

The topiary maze at the Habsburg hunting lodge.

Apartment complexes built into huge repurposed natural gas tanks.

Op-art architecture designed for happiness.

The Habsburgs' royal collections of art and wonders.

The final resting place for the remains of 143 Habsburg royalty.

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

The solemn exterior conceals an opulent interior of this 17th century church.

A silly medieval mural preserved on the side of a Viennese house.

Legends surround an ancient tree trunk riddled with nails for good luck.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Golden Gate Park's historic collection of plants.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

According to a satirical conspiracy theory that persists today, this German city of 300,000 is a hoax invented by the CIA.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

This unique Renaissance castle was turned into a home for Nazi occultism.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

A two-inch thick solid brass rod that extends an astounding one kilometer straight into the earth.

This German museum is devoted to all aspects of grave culture from headstones to coffins.