A wooden street sign is the last remnant of this 400-year-old alleyway.

Stockholm's narrowest alley is barely over two feet wide.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

"Only the dead get off at Kymlinge."

A modern, secular take on a traditional Virgin Mary motif.

Swedish mice can dine at the Nuts of Life restaurant or take a date to the amousement park.

This poignant sculpture of a gnarled weapon is a symbol of non-violence.

The trailblazing Swedish businesswoman created a beloved minty candy called polkagris.

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

It houses the remains of a 17th-century version of the Titanic.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Catalonia Tradition: Beating the hollow Christmas log until it defecates in your fireplace.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A beautiful but toxic fountain of mercury.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This 19th-century fountain's namesake animal isn't what you think it is.

Giant topiary dog once played a role in a terrorist bomb plot.

Hindu temple of the dead home to hundreds of long-tailed macaques.

A sprawling nature preserve harbors the world's only living dragons.

A flooded Mexican cave that hides a river beneath the water.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

The famous artist couple lived and worked here, in two different houses separated by a bridge.