The largest mosque in Germany.

This ducal residence was once home to a future Russian empress and a French king in exile.

This German art chapel is perfect for those who like their worship hard, modern, and utterly alien.

A ruined castle stands atop a hill surrounded by dragon lore.

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

A top-secret bunker now turned museum, is an eerie look at what life would have looked like in the event of nuclear war.

The door to the museum holds a unique artifact from the Finnish Civil War.

One of the oldest structures in Helsinki is this burrow grave that dates back to the Bronze Age.

One of Belgrade's most beloved animals.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

A misnamed well, with a deep dark past.

A Serbian church lit by chandeliers made of weapons.

This statue of a goat in boots is meant to represent the European Union.

This art installation pays homage to the famed stones of European lore.

A pair of connected skyscrapers form this symbolic gateway.

The unusual sculptures are believed to be powerful political symbols.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

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

A beautiful 19th-century mansion slowly crumbled and became a 'ghost house' after World War II.

Backwards hour and minute hands and a timing mechanism that fluctuates with the temperature led to this clock tower's local nickname.

A maze of underground tunnels beneath one of the most beautiful forts in Serbia.

Near Belgrade, an ancient-looking sarcophagus serves as a World War I monument.

At this archaeological site, visitors can explore the ruins of the capital of the former Roman province of Moesia.

The final resting place of one of the first alleged vampires.