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

A portable, wooden replica (minus the hyphen) of Hamburg’s iconic crooked coffee shop.

A tiny island is connected to the mainland by a private railway that residents travel in their own personal wagons.

Solar observatory doubles as a daring display of Expressionist architecture, much to Einstein's chagrin.

The history of German architecture is explored across this fairy-scale mini-city.

A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

A stairway to heaven, or to nowhere at all.

This former steel and coal plant is now a neon-lit industrial fantasia.

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

Europe's largest natural bridge has a 19th century royal chateau built into its side.

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

Built to test magnetically levitated elevators, the tower also boasts Germany's highest visitor platform.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This ancient theater was once the home of fierce gladiatorial battles.

Abandoned medieval hill town.

Ernest Hemingway was the first to sign this colorful wall covered in thousands of celebrity signatures.

Giant, pink stuffed rabbit on an Italian mountain.

These medieval ruins have survived since the 12th century, even providing shelter from the Nazis.

The location of the last witch trials of Italy, known as "The Salem of Europe."

An ancient rogue artist community hidden next to one of the world's most glitzy and glamorous cities.

There once was a man named Lear / Who found limericks so dear / His final resting space / Is an unusual place / Most people don’t know he’s here.

For a brief time in 1960s France, families could climb into a tiny submarine and be pulled along an underwater journey.

A crumbling island fortress that seems to be covered in a field of stone crosses but is simply incomplete.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.