This abandoned Slovenian military barracks has become a punky-political art squat.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

The medieval ferry service has been going strong since the 14th century.

This 15th-century church houses priceless works of art from a range of Croatian artists.

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

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

This Croatian island is for sale but no one is buying due to the dozens of accused Nazi sympathizers who were massacred there after WWII.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

This picturesque medieval monastery guards a small trove of historic treasures.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

A peculiar museum that includes many drunken tales, a drunk driving simulator, and much more.

Dedicated to the writer who immortalized the use of the poppy as a symbol of remembrance of those who died in wars.

Legend has it the lovelorn tears of a princess and a shepherd boy formed the blue and green twin lakes in the Azores archipelago.

One of the oldest art supply stores in the United States.

This museum offers an actual time machine back through Colorado's past.

A downtown park built on top of unclaimed graves.

A Rocky Mountain city provides a happy ending for a pinto pony and his Brobdingnagian red chair.

A multiversal transit station located right below a highway interchange.

The huge collection of paintings of the American West is one of Denver's best-kept secrets.