These purpose-built WWII air raid shelters, which run half a kilometer under the town of Mellieħa, are among the longest in Malta.

Ancient mysterious ruts carved in the bedrock.

At more than 5,000 years old, these structures are among the oldest free-standing stone buildings in the world.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

One of Serbia's oldest luxury hotels and a nostalgic echo to Yugoslavia in the state's former capital.

A well-worshipped shrine to the Virgin Mary nestled inside the last of Zagreb’s historic gates.

A house that transports visitors back to Yugoslavia.

This 135-year-old weather station studied the effects of the climate on human health.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

Where the lovelorn find a home for their sentimental keepsakes.

A unique interactive experience of everyday life in communist Yugoslavia—a very different time in Croatian history.

Bridge that died in war and was resurected.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

This automated sculpture of two men peeing will spell out text messages with their micturition.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

The first museum in the world devoted to sexual gadgetry.

Macabre astrological automaton clock dating to the late 1400s.

The hidden lair of an alchemist rediscovered in a 2002 flood.