This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

This piece of early engineering is rather unknown despite its location in the heart of Madrid.

Turntable anonymously received orphans, alms, and groceries.

A statue dedicated to the founders of communism.

Featured in one of the most iconic scenes in cinema history.

These massive moving sand dunes have swallowed an entire village and are still on the run.

This open-air museum was originally a World War II testing ground for German missiles and rockets.

A radio telescope for listening to the stars, based in one of the cloudiest countries in the world.

This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

The 20-mile causeway that separates the Netherlands from the sea.

A miniature city, once ruled by the Queen of the Netherlands.

An opulent monument built for a duke who donated his entire fortune to the city of Geneva.

The birthplace of a famous steak sauce still keeps its recipe a secret.

Located inside Hoge Veluwe National Park, this museum began as the private collection of a prominent female art collector.

Go inside a revolutionary, cage-less zoo where 35 species live and some of them roam free alongside their human visitors.

Oriental bazaar in the heart of Sarajevo.

This red light district plaza memorializes the Fab Four and their historic connection to the area.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

People have been placing babies on these lilies for photoshoots since the Victorian era.

Graffiti covers the walls of a room where university students through the centuries have waited nervously to defend their theses.

This historic Dutch newspaper building is covered with media-themed details—and one unrelated oddity.