Mysterious craters may have been home to an ancient cult.

A forest park outside Tallinn full of architectural and artistic curiosities.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

Made from trees and then abandoned, this fence is still growing along a path in Germany.

An alchemist's "magic door" stands in the middle of a Roman park.

An abandoned horror film set sits eerily along a highway through Hollywood's "door to the desert."

The largest cactus farm in Africa.

Building owners can take out tiles for free at this repository for historic building materials.

The Belgian royal family's private depot now stands abandoned and forgotten alongside the tracks.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Lavish royal estate punctuated with heated greenhouses.

A natural wonder in south Denmark.

Hitler's bleak vision of relaxation still stands as a mostly abandoned 10,000-room resort complex.

An unusual bronze bus shelter is actually an art installation commenting on the city's history with the Nazi party.

At this unusual park, domes, ladders, chairs, and more are made from trees.

"The most colorful grottoes of the world.

This German museum devoted to the simple wonders of salt is actually built over an old saltworks.

Europe's largest natural bridge has a 19th century royal chateau built into its side.

Living trees form the structure of an open-air palace.

In addition to fine dairy products, the world's most beautiful milk shop also offers a feast for the eyes.

The industrial monstrosity known as Bagger 258 is a colossal mining machine built in the DDR - but now left for dead in a German field.

Retirement home for giant obsolete machines.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

This decommissioned nuclear power plant offers tours of its Communist-era control room and reactor hall.