The smallest museum in Basel, Switzerland, is a two-foot-by-two-foot window in the door of a 600-year-old house.

An unassuming Swiss institution houses Europe's largest toy museum.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

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

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

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Giant topiary dog once played a role in a terrorist bomb plot.

The largest underground church in Europe.

Ancient paintings known as the "Sistine Chapel of Cave Art."

This 135-year-old weather station studied the effects of the climate on human health.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

Nibble as you learn about Slovenia's longstanding tradition of making beautiful honey cookies.

This one-time health resort was used by aristocrats around the world.

A whimsical bridge adorned with decorative dragons.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

The first mosque in the world to receive electricity.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

Oriental bazaar in the heart of Sarajevo.

Inat Kuća, or "House of Spite," is more than just an oddly named restaurant.

The place where World War I began.

Bridge that died in war and was resurected.