Designed as a reminder of one of the darkest moments in Austrian history.

More than a millennium's worth of municipal records preserve the political history of Austria.

Museum devoted to the artificial language of Esperanto.

Apartment complexes built into huge repurposed natural gas tanks.

Legends surround an ancient tree trunk riddled with nails for good luck.

Handsomely crafted representations of our round planet.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Baroque celebration of the end of the Great Plague of Vienna.

Catch a scenic view of Warsaw's Old Town from the top of a centuries-old dumping ground.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

A statue honors the children who fought Nazis in Poland.

A menacing statue of this mythical creature can be seen at the legendary site of the monster's lair.

These plaques found across Warsaw commemorate the sites where executions or battles took place during the German occupation.

This enormous 32-foot painting depicts Poland's greatest medieval battle in glorious detail.

One of the world's largest collections of medieval religious art.

This hidden collection of everyday objects illustrates life within communist Poland.

The medieval center of the Islamic world was also once the seat of Saladin's sultanate.

This colorful and quirky set of pegasus sculptures celebrate the works of poet Zbigniew Herbert.

Modern art commemorates one of the first military actions of World War II.

This antique thermometer honors the creator of the first universal temperature scale.

A huge wooden clock that is so beautiful its creator was forcibly blinded.

A mysterious emblem tucked in an small alleyway is actually the coat of arms of a heroic medieval family.

Model Trains and Much More in Hamburg.