Thousands of flowers create enchanting pink tunnels over the city streets.

Statues of a fire-breather, a clown, and a whole performing troupe celebrate Luxembourg's creative side.

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.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

A rare chance to ride one of the few continuous elevators still in operation.

Fantastic views and thousands of love locks.

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 Harry Potter films.

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.