Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

This small condiment museum makes all manner of mustards with a 200-year-old mill.

The largest mosque in Germany.

The "Prussian Versailles" that is as glorious today as when it was built.

In the summer of 1957, a massive architectural exhibition showed off the future of urban living in this German neighborhood.

After local authorities changed the design, the building's architect, Le Corbusier, wanted nothing to do with it.

Designed to resemble foreign architecture, this mosque-looking structure was used to pump water to a royal fountain.

If you visit the burial place of King Frederick the Great, you'll likely find a couple of potatoes sitting on his tombstone.

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

Once considered one of the three great Augustinian churches in the Iberian world.

An architectural marvel that combines Gothic architecture with Indian elements.

The second largest monolith in the world was once betrayed by its lover, Ben Aicha.

"We gonna rock down to Electric Avenue, and then we'll take it higher..."

The Tudor-style cottage in the middle of the square is not quite what it seems.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

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

An awesome blend of traditional architecture and street art.

Some believe this abandoned Brutalist masterpiece inspired George Lucas's Sandcrawler.

The ancient heart of Tunis is an enormous maze of narrow streets and alleyways.

The fight to make Bengali an official language started in this stunning university hall.

Ancient and modern architecture are joined in Louis Kahn's monument to democracy.

The untimely death of a dignitary's daughter led to this fort being abandoned before it was ever finished.

This colorful palace is an oasis of calm amid the hustle and bustle of the Buriganga riverfront.

Model Trains and Much More in Hamburg.