Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

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

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

Turntable anonymously received orphans, alms, and groceries.

Week-long block party becomes a competition for the best decorated street.

Mountain where Jesus was first tempted by the Devil.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Cursed swimming pool left abandoned is now a favorite of filmmakers and ghost hunters.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

The oldest stone house in Paris was built by its most famous alchemist.

During the summer months, giant teddy bears take over Paris near Les Gobelins metro station.

Europe's largest community of crocodiles and alligators.

The sunken structure looks like the victim of a catastrophic flood.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

The ruins of a medieval castle linked to the murderous French lord that inspired the famous legend of Bluebeard.

This tiny hotel perched atop a 50-foot tower really puts things into perspective.

Sleep in the hay, spin the wheel and eat grain pellets to your heart's delight.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This symbol of the French Revolution still stands where it was first planted during the 18th-century.

This unique medieval artwork featuring the story of the Antichrist remained lost for decades.