The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

The remnants of a WWI naval mine that once terrorized the country now decorates a street.

Once housed in the towers of this Gothic church, this 17th century clock still ticks today.

This pair of gilded girls atop an Art Deco building in Copenhagen were built to function as a weather indicator.

The only surviving piece of Copenhagen's 16th-century defensive wall.

This 1st-century CE Roman bath sits under a carpark.

This curious building hides eclectic details like medieval gargoyles alongside naked angels and Art Nouveau mosaics.

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

Third time's a charm, or in this case, two testicles are.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

The secret medieval communication system will whisk your words above the noise of the crowd.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

This unique museum doesn't shy away from highlighting Qatar's role in the history of slavery.

The tomb of the mythological founder of Padua is not hidden in some obscure crypt, but stands right in the middle of the city square.

Something's missing between the arcades of the Palazzo della Ragione in "the city of the three withouts."

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

A memorial to honor those who were killed in a Bastille Day terror attack in Nice.

Liechtenstein's royal family calls this medieval alpine castle home.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

In one of the world's smallest countries, a royal's personal winery is open to the public.

Browse through a century of this principality's first popular export.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

The cutest way to stay safe in traffic.