An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

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

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

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

A surreal statue honoring Prague's favorite literary son.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

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

A saintly relic hidden in a Prague church basement.

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

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

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

Macabre astrological automaton clock dating to the late 1400s.

The Slovenian architect designed many landmarks in the capital city, including his own dream house.

A cemetery for Slovenian notables also serves as a popular recreation space.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

A whimsical bridge adorned with decorative dragons.

This abandoned Slovenian military barracks has become a punky-political art squat.

A miniature train-ride through Slovenia's largest cave system.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This massive subterranean fissure is known as the "underground Grand Canyon."

A black cat protests the City Guild in Riga's Old Town.

Flamboyant architecture from the turn of 20th century.

A decommissioned submarine base makes a great space for graffiti art.

Only a fragment of this 15th-century Dance of Death survives today.