Floating swimming pool within a moored vessel.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This watchtower once presided over the Berlin Wall.

This obscene artwork on the side of a newspaper office pokes fun at a rival paper's former editor-in-chief.

A crucified and bearded female saint.

The oldest garden in Prague, once part of an medieval orchard.

A museum in the building where Nazi Germany signed its surrender tells the story of World War II from the Soviet perspective.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

Art and a pun, all in one.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

The medieval "Bearded Man" relief still serves as a clever flood warning marker.

A controversial artwork draws attention to the dark history of Prague's "Suicide Bridge."

A striking symbol of the Bulgarian capital.

Elaborate tile work in this railway station tells the story of Portugal.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This museum is home to one of the biggest collections of printing press technology—plus a river view.

The stunning interior of this Gothic church is covered in ornate gold details.

A small but charming botanical garden that contains many exotic plant species.

A hidden three-foot-wide house separates these two regal churches.