The ruined remains of the airport Claus von Stauffenberg departed in his failed attempt to kill Adolf Hitler.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Stonehenge has nothing on Castlerigg’s views.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

Ruins of a German Castle on top of a towering stone pillar.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

Longest fortress system anywhere in Europe.

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

These massive moving sand dunes have swallowed an entire village and are still on the run.

Bizarre living fossil only grows in a small chunk of the Namib Desert.

Largest cave system in Africa.

Sloth rehabilitation center in the jungle of Costa Rica.

The world's second largest single-dish radio telescope, once used to contact E.T.

This abandoned five-star hotel is now a five-star urban exploration destination.

This enchanting Victorian estate was home to the world's first hydroelectric power generator.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

This 13th century castle is chock full of ghosts and impossibly rare cows.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

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

The longest and tallest aqueduct in Britain can actually be sailed across.

A former fisherman's hut deemed too small for habitation is now a delightful tourist draw.