Apartment complexes built into huge repurposed natural gas tanks.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

A unique hotel for the artistic soul.

The resting place for anonymous victims of the Danube's dark waters.

A cableway for car transport.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Once the home of a hermetic monk, this cave now houses a small church.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Massive installation of Europe's negative stereotypes.

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

The soulless eyes of 82 bronze children stare on forever in remembrance of a horrifying World War II massacre.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

This bar and museum are devoted to the controversial comic book work of Kája Saudek.

The first museum in the world devoted to sexual gadgetry.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

A mocking tribute to the past and modern leadership of Prague.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

Op-art architecture designed for happiness.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

After 11 years of reconstruction work, Slovakia's finest hilltop chapel complex is finally reopen to the public.