Strange rumors surround the artist who created these solemn metal guard dogs.

This former railway facility is the oldest in Slovenia, and now houses a museum showcasing the history of steam locomotives.

A beautiful drive through the foot of the Alps traces the path of 15th-century Turkish raids.

The monument honors the mountaineers who were part of Europe’s best anti-Nazi forces.

A cemetery for Slovenian notables also serves as a popular recreation space.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

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

A crumbling World War I fort that is reached through a series of concrete tunnels.

An artsy hidden staircase leads to breathtaking views of San Francisco.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Abandoned since 1998, this train station has become an oasis for urban explorers.

This bike path was sunk below water level for maximum wonder.

A Cold War command center is hidden under an idyllic countryside.

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

An open-air sewer system that was covered piece-by-piece over 300 years.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

This Greek temple, open only an hour a day, was the site of a war of tastes between an architect and an artist.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

This abandoned Belgian fortress is purposefully being left to nature.

During World War II, this rice mill became a Nazi concentration camp.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

This man-made mound monument was built out of soil from all across the Polish empire.

There are thousands of tributes and memorials to the King, but none quite like this one in a Kraków city park.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.