The blood-soaked ruins of the castle where the murderous Blood Countess was walled in alive.

This ruined castle perched atop a rocky peak is a great place for a hike.

Tall columns of volcanic basalt make up this improbable-seeming rock formation.

This network of conjoined cellars was riddled with traps and supposedly allowed the townspeople to pretend their homes were deserted.

This former quarry is now a picturesque gorge that hides a sunken lake.

A spiral staircase twists to the top of this unusual Czech lookout tower.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

A church of bones, decorated with 40,000 human skeletons.

Digger attempting to hide itself under 300 tons of rubble.

These old World War II fortifications have been transformed into an unusual equine attraction.

The world's first combination ski slope and power plant.

Remnants of the Nazis' occupation of Denmark linger along the sand.

Tiring of digging out the door to this church for every service, it was eventually abandoned to the sands.

An abandoned lighthouse awaits its destiny: being buried under shifting sand.

Four alabaster giants contemplate the tides on the shore of Denmark.

A walkable map of the world, made from soil and stone by one man.

A decaying, yet still functioning, work of communist architecture.

A massive cave once a secret military base is now home to thousands of bats.

Crossing a suspension bridge above a forest is the only way to reach this 12th-century monastery.

One of the largest mines in Bulgaria is now home to a vast museum more than 100 feet underground.

Not far from a popular beach, an unfinished, abandoned mansion for Bulgaria's last communist dictator.

These natural cliffs look like they are a part of an old castle complex.

Rock carving created 1,300 years ago 75 feet off the ground.

An unfinished complex built for children from around the world sits abandoned on the Black Sea coastline.