Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

One of the largest ossuaries in Spain is packed from floor to ceiling with bones.

This magical space partly designed by Antoni Gaudi is one of the best examples of romantic gardening in the Mediterranean.

A Franco-era dam flooded (almost) everyone out of this centuries-old Aragonese town.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

Bacteria and algae give the salty water its bubblegum hue.

An architect transformed this abandoned cement factory into his castle-like workshop.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A small artistic "graveyard" where clichéd expressions have been buried.

This legendary dive bar boasts a collection of over 1,300 clown figurines.

This antique farmhouse is one of Læsø's rare seaweed houses.

Traditional Danish spot where the schnapps are flowing and the smørrebrød is loaded.

A 15-foot-tall statue of the head of the Sopranos family greets passengers at a train station in southeastern Lithuania.

The Frank Zappa fan club erected this monument to their prog-rock hero to mark a new era of post-Soviet Lithuania.

You would never guess that before World War II this lonely field was a bustling German city.

A tiny traditional village keeps an ancient method of beekeeping alive.

A top secret Cold War bunker hidden beneath a Latvian spa facility is now open for tours.

Spend the night in 1920s Latvia in this historic recreation and movie set.

This fortress-like monastery is covered with intricate frescoes.

The kitsch mansion of the former Romanian president Nicolae Ceaușescu features a golden bathroom.

An old spa town in the mountains of Romania where, according to legend, the great hero Hercules once bathed.

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

A late-medieval Dutch castle with trick fountains in its whimsical water gardens.