This snug medieval lane is one of the narrowest streets in the world.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

Gigantic Romanian salt mines used to heal respiratory conditions.

A muddy alien landscape that is home to rare species of exotic plants.

This Romanian village may have been drowned, but it is long from forgotten.

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

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

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

Moss and stone turn this waterfall into an otherworldly liquid veil.

In the fictional world of Kcymaerxthaere, standing at this site just outside Vienna, Austria, the sky would have been found beneath your feet.

Two nations form a rare four-sided border at the peak of a mountain, philosophical questions result.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

The medieval network of canals hidden underneath the city is opened to explorers each year.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

A silly medieval mural preserved on the side of a Viennese house.

A unique opportunity to stay the night in retrofitted sections of sewer pipe.

American soldiers discovered Europe's best one-liner at the end of World War II.

The world's oldest known salt mine.

Legends surround an ancient tree trunk riddled with nails for good luck.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

Each year melting snow turns these Austrian hiking trails into scuba zones.

Where beer lovers can literally immerse themselves in beer.