This small chapel built into rock is the oldest place of worship in Luxembourg.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This magenta statue commemorates the legendary marriage between a mermaid and the city's founder.

An ancient Roman relief beautifully preserved on the façade of a house.

The official motto of Luxembourg reminds passersby of the Luxembourgish commitment to their national identity and sovereignty.

A small museum dedicated to mustard making inside a still-working mill.

Statues of a fire-breather, a clown, and a whole performing troupe celebrate Luxembourg's creative side.

Some believe that the artist behind this whimsical statue inserted his own likeness as a way to discreetly flip the bird.

Healing waters from a holy well, previously used by locals for doing laundry.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

The final resting place of the last "gypsy king" of Poland.

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

A heavily politicized roundabout discussing the state of a heavily politicized country.

Warsaw's fantastically preserved gasworks...almost.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

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

In the summer, the area around this sculpture transforms into a vibrant concert venue.

At night, this memorial illuminates a ghostly outline of a footbridge that connected two sections of the Warsaw Ghetto.

Legend says this is actually a heartbroken prince waiting for his true love's kiss.

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

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.

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

A bronze replica of an elm tree that honors the victims that perished in Pawaik Prison.