Touching this 18th-century Scottish philosopher’s toe allegedly conjures good fortune.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

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

A museum dedicated to the history and exploration of both popular music and science fiction.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

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

Op-art architecture designed for happiness.

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

The unusually large seat sits atop the base of a ruined temple.

These tenacious 14th-century towers defied demolition and are now a fairytale vacation rental.

The telescope that discovered Neptune.

The scars of World War II are preserved on its walls.

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

This beautiful 19th-century temple stands atop the ruins of its predecessor.

A serious museum dedicated to two German comedians.

An abandoned train station in Munich constructed for the 1972 Olympic games.

The small alleys in Lübeck's Old Town are a result of medieval urban sprawl.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

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

The skeletal frame of a decommissioned gas-pumping station offers breathtaking views of greater Berlin.

The prison where Hitler wrote "Mein Kampf," and 278 Nazis were later executed for war crimes.