One of the best examples of a Byzantine period monument in Albania.

The largest Roman amphitheater in the Balkans once held over 20,000 people, but managed to lay hidden for hundreds of years.

This beautifully preserved Ottoman house is steeped in history.

This ominous Albanian fortress houses tanks and downed planes as a reminder of their victories over Western imperialism.

A museum dedicated to secret surveillance.

In the heart of Tirana, this underground nuclear bunker has been transformed into a museum.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Norway's national monument to fallen seamen.

The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

A catapult rock from Gotland’s 13th-century civil war is still lodged in Scandinavia's best-preserved medieval city wall.

Known locally as the Jungfrutornet, this Medieval tower hides a dark legend.

Europe's only museum solely dedicated to the history of whaling still has a fully-functioning whaling ship.

These massive animal sculptures were constructed as part of a reality TV show challenge.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

A fantastical display of Croatian folklore, mythology, and myths.

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

A house that transports visitors back to Yugoslavia.

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

This only museum in the world dedicated solely to mushrooms.

This antique thermometer honors the creator of the first universal temperature scale.

A merchant court dedicated to the fictitious King Arthur is heavily adorned with bizarre Renaissance art.

Memorial to the lost dead of Gdansk, whose resting places were destroyed during World War II.

These rare statues are one of the few remaining material witnesses to Old Prussian culture.

This one-of-its-kind shipyard brings the 12th-century Viking Age back to life.