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

A fearsome dragon clings to a corner of Munich's city hall.

The last bastion of Roman presence north of the Alps looms over a German town.

The footprint of a frustrated devil in Munich's Cathedral.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

The most visited, and possibly most controversial, museum in Germany.

The fairy tale castle of the "fairy-tale king."

World's largest bell sits on the grounds of the Kremlin in Moscow.

Moscow's imposing monument to the Space Age.

Moscow's most popular cemetery includes the graves of numerous cosmonauts.

Museum celebrating the achievements of the Soviet space program.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

A moving memorial to the fallen and missing from WWI trenches.

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

Theme park featuring miniature replicas of European monuments.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

Climb inside an iron crystal magnified 165 billion times its normal size.

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

Home to the world's oldest functioning orrery.

A collection of biblical memorabilia.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

Historic medieval fortified city in southwest France.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.