A silly medieval mural preserved on the side of a Viennese house.

Eighty million natural history specimens call this gargantuan museum home.

An unusual round church in London with a Templar past.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Cold war icon and onetime "hole" in the iron curtain.

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

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

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

Hamburgers are intensely proud of their tunnel beneath the river.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

Model Trains and Much More in Hamburg.

The site of Austria's biggest concentration camp now honors its victims.

This "mathematical tower" was an observatory, early skyscraper, and place to reflect on all of nature and the cosmos.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

The world's most important buildings shrunk to a tiny size.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Apartment complexes built into huge repurposed natural gas tanks.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

The world's oldest known salt mine.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Ride a dragon train into a world of dwarves.