Four-story slides send people whizzing through the math department at this Munich university.

This museum promotes informed contraception by documenting its often secret past.

This small chapel is built of human bones and decorated with a golden skeleton.

Perhaps the most spectacular grotto along the Algarve coastline.

This unassuming chapel in Portugal plays host to a ghoulish collection of bones.

The Habsburgs' royal collections of art and wonders.

Dine amidst exotic plants at this former royal greenhouse.

Apartment complexes built into huge repurposed natural gas tanks.

An IT-specialist-turned-farmer reintroduces an Austrian food tradition while promoting snails as a sustainable "future food" option.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

Apparently, Hell has waterfalls in Slovenia.

This cutting edge museum details the history of skiing, from its ancient origins to its status as a sport.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

A whimsical bridge adorned with decorative dragons.

Humble beginnings for one of the world's most famous scientists.

A series of playful yellow penguins share a serious message about the environment.

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

A half-buried vehicle in Prague's is the latest iteration in a long-running piece by Czech artist David Černý.

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

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

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

Countless grotesque faces stare out from this eerie Prague art wall.

A Jenga-style cylindrical tower of books that appears to go on forever.

A line of abandoned, alien-like fortresses dot the mountains of North Italy.