This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

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

A crumbling World War I fort that is reached through a series of concrete tunnels.

The summer residence of a Spanish ambassador who brought viticulture to an impoverished region, sparking its transformation into one of the world's best wine regions.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

The "dragon babies" of southeastern Europe.

A miniature train-ride through Slovenia's largest cave system.

A beautiful drive through the foot of the Alps traces the path of 15th-century Turkish raids.

An otherworldly alpine pasture with its own unique microculture that recalls Middle Earth.

This small Slovenian town has become a magnet for microbreweries.

A trough of 700 strange bronze faces runs through a narrow alley in Ljubljana's old town.

In between two buildings in Ljubljana, medieval tunnel to nowhere.

A whimsical bridge adorned with decorative dragons.

A public work of art that also provides some relief from the summer heat.

Crushed coral and crystals give the sand its signature coloration.

Stalactites and stalagmites in a beautifully lit cave.

The hands on this clock appear to be created by two workers sweeping debris into careful positions.

Europe’s oldest natural human mummy.

The oldest skyscraper of Europe now stands dwarfed by the surrounding structures.

The oldest statue in the Netherlands has survived relocation, bombardment, and burial.

A statue of the second-tallest Dutchman in history.

A giant floating rubber duck-bunny painted with a different design every year.

From afar it looks like someone's hat blew into the water, but closer inspection reveals a giant floating sculpture.

The fairy tale castle of the "fairy-tale king."