Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

A brush maker used his factory to protect blind Jews from the Gestapo.

One of downtown Berlin's last reminders of its Communist past.

This unique bridge physically lifts a piece of the road into the air to let boats pass by.

Amsterdam's former hotspot for public executions and dissections.

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

This disused VLF radio station is no longer in service but the surrounding town still bears its name.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Tiny memorials honor individual victims of the Holocaust.

The 20-mile causeway that separates the Netherlands from the sea.

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

A surreal statue honoring Prague's favorite literary son.

Its town washed away centuries ago, this lonely tower by the sea tells the tale of a mermaid and a curse.

There are two dozen tanks just sitting in an open field in Lower Saxony.

An awe-inspiring giant blue whale jaw bone stands in the center of this Dutch island.

Go inside a revolutionary, cage-less zoo where 70 species of monkeys roam free alongside their human visitors.

Hiding the longest subterranean river known in the world.

After a nearly successful attempt on Hitler's life, the conspirators met their fate in the courtyard of this Berlin building.

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

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

Cold war icon and onetime "hole" in the iron curtain.

The largest 19th century panorama in the world still in-situ.

Looming communist pillar with a Czech twist.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.