More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A whimsical art tower at a Bavarian brewery includes a grotto for its mythical beer-brewing dwarves.

This lurid German fountain plots the sad course of marriage from dating to death.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

A beautiful collection of taxidermy birds and rare pomological wax models.

These paved rills bring freshwater into Altstadt and could spell wedding bells for whoever stumbles into the waters.

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

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Cold war icon and onetime "hole" in the iron curtain.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Named after the German word for "a longingness to travel," this park brings together thousands of city and street signs from around the world.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

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

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

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

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

A cannon designed to fire an atomic warhead.

A hidden barn-sized rendition of Grant Wood's most famous, and most parodied, painting.