The first mosque in the world to receive electricity.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

Inat Kuća, or "House of Spite," is more than just an oddly named restaurant.

An officers prison camp believed to be impregnable by the Germans saw over 30 successful escapes.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

A mocking tribute to the past and modern leadership of Prague.

The first museum in the world devoted to sexual gadgetry.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

This spooky statue sits outside a famous Prague theater.

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

Bullet holes in the church wall are a reminder of the violence that followed the assassination of a high-ranking Nazi officer.

A series of playful yellow penguins share a serious message about the environment.

Beloved children's TV characters freckle the German city's streets.

Tourists often confuse this beautifully ornate former cigarette factory for a mosque.

This underground transport hub doubles as an art gallery.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Mysterious hillside with a continuously burning natural fire.

A shrine of fire worship built on top of a natural flame.

Resonant stone, that has been played since prehistoric times.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

A gigantic collection of teeny, tiny books.