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.

An abandoned swimming pool decays on the outskirts of Berlin.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

A geometric jumble of homes.

After over 100 years out of service this landmark windmill once again turns as a symbol of Jerusalem's self-sufficiency.

Tel Aviv's popular neighborhood went though endless waves of transformation.

A mechanized clock where a man fights off a dragon, crab, and rooster.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Monument to a suicide protesting the Soviet invasion.

This obscene artwork on the side of a newspaper office pokes fun at a rival paper's former editor-in-chief.

Tiny memorials honor individual victims of the Holocaust.

A slice of central Asia in the middle of Berlin.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

A surreal statue honoring Prague's favorite literary son.

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

The hidden lair of an alchemist rediscovered in a 2002 flood.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.