This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

This massive library holds what was once the largest book collection in the world.

Peek through a transparent pyramid and drink in the mountain made of books.

The world's oldest Jewish library was founded by Sephardic Jews in 17th century Amsterdam.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

Floating swimming pool within a moored vessel.

The great Danube river starts here.

In this brilliant blue spring in Germany, legend has it that a sad mermaid learned to finally laugh.

Museum in a swimming pool where the water still flows.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

The telescope that discovered Neptune.

A Nazi concentration camp and Anne Frank's place of death.

Hamburgers are intensely proud of their tunnel beneath the river.

While you wait to cross the street at a traffic light in Mainz, you might notice that the light is staring back at you.

This unique exhibit "Dialogue in the Dark" reverses roles as the visionless become guides and the sighted become ‘blind.’

Final resting place of the humble physicist who discovered X-rays, and made the invisible visible.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

This bakery and museum offers tours of the tastes and mythology of Aachen's signature spice biscuit—just don't ask for the recipe.

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 monumental home of Prussia’s eccentric "Cannon King."