Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

Op-art architecture designed for happiness.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Baroque celebration of the end of the Great Plague of Vienna.

When this monument to Slovenia's national poet was erected, it's said to have sparked the ire of nearby church authorities.

A whimsical bridge adorned with decorative dragons.

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

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

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

This curious, round temple is the oldest still-standing marble building in Rome.

Ancient ruins hidden underneath a modern luxury hotel.

This ancient market is often referred to as the oldest shopping mall in the world.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Christ's blood allegedly preserved in a Belgian town.

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

The legendary giant's severed hand sits on Antwerp's popular shopping street.

Cozy basement bar sports an inventory of over 2,000 beers.

A little sculpture with a large wardrobe.

This bridge was constructed from the rubble of the infamous Bastille.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

This modest marker near Notre Dame identifies the very center of Paris.

London's smallest police station is barely the size of a phone booth.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.