This still-celebrated home was a radical architectural experiment in 3D De Stijl.

'The Letters of Utrecht' lays out a ribbon of poetry one letter at a time, with no final verse in sight.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

The abandoned club hides in the hills of Ibiza.

Originally slated to become a luxurious resort, this structure is now a graffiti haunt reclaimed by nature.

Inside a former smuggler's cave, an artificial waterfall and light show.

This ironic war memorial thumbs its nose at a campaign of inedible humanitarian aid food products.

This enormous abstract sculpture is part jungle gym, part elaborate noise-making machine.

A war-torn Olympic relic is being overtaken by graffiti and nature.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

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

The place where World War I began.

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

The first mosque in the world to receive electricity.

A monument on the pavement marks the spot where two cultures that shaped Sarajevo come together.

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

Oriental bazaar in the heart of Sarajevo.

A unique interactive experience of everyday life in communist Yugoslavia—a very different time in Croatian history.

Gargoyle head that brings good luck.

An ancient knight and a symbol of the city's freedom.

Picturesque basketball courts sheltered by historical defensive walls and with an enviable sea view.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This magenta statue commemorates the legendary marriage between a mermaid and the city's founder.

The official motto of Luxembourg reminds passersby of the Luxembourgish commitment to their national identity and sovereignty.