Stockholm's deepest subway station is also a stunning ecological wonder.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This pair of unsuspecting buildings are in fact the very first modern skyscrapers in Europe.

When this 18th-century observatory's meridian was moved, it set Sweden's time back by 0.04 seconds.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

Kuwait City's uniquely designed water towers look straight out of a retro sci-fi cityscape.

These 4,000-year-old tombs form a surreal landscape.

This centuries-old tree tells an unusual tale of vegetation and fertility in the desert.

Skyscraper powered by wind turbines attached between its towers.

Is this amazing tableau depicting Gilgamesh and Enki 4,000 years old?

This innocuous-looking button may have been used to assassinate a king.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The world's biggest version of the popular Swedish souvenir.

A centuries-old copper mine that once provided two thirds of the world's copper supply.

A reproduction of a mysteriously preserved body found in the 18th-century and put on display for years before burial.

Order “Proletariat’s Cutlet” at this communist-themed restaurant allegedly once visited by Lenin.

The world’s narrowest house makes for an awkward, four-foot-wide living space.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

A stunning gilt bronze relief denounced by Hitler as "degenerate art"—even though it was dedicated to the Nazi leader.

One of the oldest wine cellars in Germany is now a restaurant beneath Bremen's town hall.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

Hamburgers are intensely proud of their tunnel beneath the river.

Hamburg's first legal sex work is relegated to a gated street that still does not allow pedestrian women.