Nestled in a peaceful valley, this Armenian monastery may have been saved from Mongols thanks to the eyes of God.

This ancient village and its adjoining cemetery have a beautiful history of death and remembrance.

Fortified homes of highland warriors that are still in use today.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

One of the windiest peaks in Crimea is home to an incredible set of cable bridges.

In the land of the Light Brigade stands a testament to the Cold War.

The largest catacomb system in the world.

Handsomely crafted representations of our round planet.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

The beautiful baroque library of the Hapsburg empire.

The final resting place for the remains of 143 Habsburg royalty.

The Habsburgs' royal collections of art and wonders.

Mummified monks and the accidentally interred, in a 17th-century crypt.

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

The Natural History Museum that time forgot.

This massive underground salt mine now holds a sci-fi theme park in its depths.

No one knows who built this strange cave of worship or exactly why.

Gigantic Romanian salt mines used to heal respiratory conditions.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

Structure built from the skulls of vanquished foes.

An abandoned saucer-shaped monument in the Bulgarian mountains.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

Yugoslavia's biggest underground airport lies in ruins.