Norway's oldest cathedral still in use.

A former factory now pays tribute to a local industry fueled by sardines.

Bursting forth from a historic German neighborhood, these day-glo palaces are now a bright fixture in the town.

This strategic isle was once swapped between empires and almost entirely destroyed in a bomb explosion.

This red light district plaza memorializes the Fab Four and their historic connection to the area.

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

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

This platform is now a memorial dedicated to those who were deported during the Holocaust.

Royals, rebels, and artists have all conversed at this grand 19th-century Viennese coffee house.

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

Double spiral staircases are not unheard of, but they are very rare.

This monumental work of art symbolizes the coming together of a previously divided city.

The hilltop ruins of a border fortification in the Italian Alps that was much fought over.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

Op-art architecture designed for happiness.

The world's oldest rose is so tough it survived being bombed in World War II.

After this historic church was destroyed by World War II bombing, its blackened shell was left standing as a monument.

This gilded emblem was once stolen by a Cookie Monster impostor, who demanded a charitable ransom for its return.

No need to strap in for a "ride" on this walkable roller coaster.

This 18th-century folly is one of Europe's rare "garden mosques."

One of the biggest markets in Asia, under one of the continent's largest domes.

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

A unique look into the bowels of a century-old funicular.