A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

When the rain falls, this drain system turns into a musical instrument.

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

Yugoslavia's biggest underground airport lies in ruins.

This massive subterranean fissure is known as the "underground Grand Canyon."

Now abandoned, the world's first torpedo factory is crumbling into the sea.

This Croatian computer club features such gaming relics as the infamous Virtual Boy and an 8-bit Pacman machine.

This one-time health resort was used by aristocrats around the world.

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

A whimsical bridge adorned with decorative dragons.

"World machine" built by an untrained Austrian farmer.

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

Fantastic stories on a miniature railroad.

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

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

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

A tower marking the spot where Yugoslavia began its resistance against the invading Nazis stands neglected, but not quite forgotten.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

Remains of a station that only operated for one year.

Romania's only crater lake with water as pure as if distilled.

The last planned Soviet city was built for the former residents of Pripyat after the Chernobyl disaster.

One of the most poignant ruins of the Chernobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.