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

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

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

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.

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

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.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

London's smallest police station is barely the size of a phone booth.

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

This statue honors the thousands of Allied avians that served and died for France during World War I.

This triumphal arch celebrating the Sun King's conquest of Lille is a masterpiece of military architecture.

This monumental mural crafted nearly 40 years ago is still in perfect condition.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

An unsettling sculpture of a boy hanging out in a street in Ghent has been baffling visitors for years.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

Each time a baby is born in Ghent, these streetlights flash in silent celebration.

In the heart of Tirana, this underground nuclear bunker has been transformed into a museum.

In the hometown of the Catholic saint and Nobel Peace Prize winner, a memorial dedicated to her legacy.

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

These abundant, over-the-top monuments are so widely scattered that they define the entire compact capital cityscape, often leading to jokes about whether there are more statues than residents.