This statue and park honor the Swedish chemist Jacob Berzelius, one of the founders of modern chemistry.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

Part of an abandoned19th-century fortress hides in plain sight inside a modern office building.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

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

The final resting place to 300 Victorian-era pets hides inside the city park.

A unique tribute to the millions of animals who served and died for the British military.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

Eighty million natural history specimens call this gargantuan museum home.

The Swedish flag over this small naval fort signals that the nation is at peace.

Stockholm's deepest subway station is also a stunning ecological wonder.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

Early habitat dioramas and home of the elusive gaff, the skvader.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

This little Greek plateau is home to thousands of rustic, white-sailed windmills.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

An underground city of salt.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

A statue honors the children who fought Nazis in Poland.

A Gothic-inspired fish market is Gothenburg's best place to find loaves and fishes.