Local myth claims this is a Sears catalogue home with its windows installed upside-down.

This kitschy tavern is also home to rare early editions of "Treasure Island."

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

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

An ancient Egyptian temple in the middle of Madrid, Spain.

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.

The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A layered tribute to the work of mosaicist Isaiah Zagar.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

An airy Art Deco space devoted to the weird and wonderful folk art traditions of Mexico.

Famously misunderstood wonder of the ancient world

Europe's largest prehistoric mound – burial site of a legendary king?

The largest stone circle in the world has ended up bringing up more questions than it has answered.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Rotterdammers' dirty minds gave this santa a dirty nickname and cursed it to a life of wandering.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.