Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

The largest prehistoric cemetery on the Balearic Islands dates back over 2,500 years.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Hamburgers are intensely proud of their tunnel beneath the river.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

The prototype for all Nazi concentration camps.

This ancient ruined monastery has been destroyed by fire so many times that it seems like God hates it.

Once the home of a hermetic monk, this cave now houses a small church.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A Hungarian pharmacy museum with a box full of mummy powder.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

A 13th-century convent where St. Margaret of Hungary spent her teenage years.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

Also known as the Blue Church, the building was consecrated to the daughter of Andrew II.

The largest fountain in Bratislava.