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

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

Some believe that the artist behind this whimsical statue inserted his own likeness as a way to discreetly flip the bird.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

These sandstone replicas of a whale spine represent the history and culture of the Canary Islands.

This propeller hub is one of the last remnants of a ship that crashed off the coast of the Canary Islands.

The ruins of the first mountaintop observatory are just a hike away.

This unique rock formation is quite the local celebrity, although one day it may come crashing down.

On La Gomera, "Silbadors" communicate in a 4,000-word language of whistles.

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

Floating swimming pool within a moored vessel.

Check the time in 145 countries at once with this East German relic.

The home of Joseph Stalin during the Potsdam conference.

Unchanged for centuries, this medieval library keeps its books in chains.

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

The location of the world's first telescope demonstration.

A condensed piece of China floating in a Dutch harbor.

Rejoice at Amsterdam's ‘pop temple,’ a former church reborn as a raucous music venue.

These public toilets also provide entertainment for visitors to Amsterdam’s Red Light District.

In 1421, a drowning man prayed for his life and promised to build a chapel where he would wash ashore.

The world’s largest street art museum.

One of Amsterdam’s most popular cultural and recreational complexes is on the site of a former gas works.

Oldest World War 2-themed museum in Western Europe.

This little patch of Europe remained neutral for more than a century because of a mine.