The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

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.

A hands-off space for graffiti artists to hone and display their skills.

Preserving the research tools, unexpected inventions, and odd collections of generations of college professors.

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

Made of 41,900 pieces of mosaic, it took two years to piece together this giant egg.

The Netherlands' first car tunnel has an unusually rectangular shape.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

This watchtower once presided over the Berlin Wall.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Come for the flowers, stay for the bats!

Taxidermy of the racing horse with a huge heart, who inspired hope in the Depression.

A museum dedicated to controversial Russian pianist Alexander Scriabin.

A 360 degree battlefield experience.

The oldest funicular in Lithuania has been climbing this steep hill since 1931.

Ever-growing collection of devils in art.

The 20-mile causeway that separates the Netherlands from the sea.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.

Every winter, this former planetarium is transformed into a massive, brightly-lit Christmas ornament.

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

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

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