Floating swimming pool within a moored vessel.

No need to strap in for a "ride" on this walkable roller coaster.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

Art and a pun, all in one.

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

This historic stone bridge has an entire neighborhood clinging to its sides.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

A tilted half-timbered house from 1672 is built into a salvaged segment of a medieval wall.

The first (but not only) upside-down house in Germany.

The fairy tale castle of the "fairy-tale king."

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

This French chateau is home to the world’s largest private collection of fighter jets.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A 16th-century horror show built in a lovely Italian garden.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

These magnificent 240-year-old machines are considered distant ancestors of the computer.

A gothic church dedicated to the love of wine.

This secret Swiss fortress is disguised as a harmless pink house, complete with fake windows.

The World Wide Web was created in this nondescript corridor at CERN.

Extensive private collection of authentic Medieval devices used for human torture and execution.

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.

A 22-million-year-old sandstone cave is a natural habitat for award-winning cheese.