This mysterious series of teeny guerrilla installations sheds a whimsical light on street art in Oakland.

A trash dump made beautiful by nature's power.

A surreal statue honoring Prague's favorite literary son.

Microscopic scenes; some call it novelty, some call it art.

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

The hidden lair of an alchemist rediscovered in a 2002 flood.

Two stunning 17th-century libraries and a cabinet of curiosities.

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

A Jenga-style cylindrical tower of books that appears to go on forever.

The first museum in the world devoted to sexual gadgetry.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

One of the famous Czech artist's lesser-known Prague installations appears to be a glowing fetus affixed to a drainpipe.

The oldest garden in Prague, once part of an medieval orchard.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

This automated sculpture of two men peeing will spell out text messages with their micturition.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

What looks like a suicide in progress is actually a statue of Sigmund Freud.

Macabre astrological automaton clock dating to the late 1400s.

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

Inside this Jewish cemetery is a memorial to soldiers who deserted the German army and were executed.

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

Where once there was a train station bathroom, there is now this German burger joint.

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