This public observatory is home to the "celestial cannon," the longest pointable telescope in the world.

An abstract and eyecatching clock/fountain is the centerpiece of this little-known German city.

The largest brick bridge in the world.

The architect of this fanciful complex called it an "oasis for humanity and nature in a sea of rational houses."

This museum tells the story of lake dwellers from 4000 BC to 850 BC, replete with stilt houses and goats.

Enter the cabin of a life-sized Hindenburg replica.

Germany's longest suspension rope bridge.

The highest cold-water geyser in the world.

This fountain of a little boy that spits on passersby at erratic intervals is a town icon.

Every half hour the eye-rolling clock face sticks out its tongue to mock the good citizens of Koblenz.

If you visit the burial place of King Frederick the Great, you'll likely find a couple of potatoes sitting on his tombstone.

The "Prussian Versailles" that is as glorious today as when it was built.

Keep your eyes out for this "ghost" and walking pun.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

This monumental work of art symbolizes the coming together of a previously divided city.

Floating swimming pool within a moored vessel.

A century-old shot ball factory tower is open to the public once a year.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

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

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

Macabre astrological automaton clock dating to the late 1400s.

A series of playful yellow penguins share a serious message about the environment.

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

Nine bronze hands protruding from a wall honor the student uprising that led to the fall of Czechoslovakia's Communist government.