Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

Copenhagen's celebrated theme park and gardens.

Hamburgers are intensely proud of their tunnel beneath the river.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

This simple roadside art installation ended up sparking a folk art movement and a controversy of international proportions.

The final resting place of the father of modern biological taxonomy.

A small church in Uppsala hides the grave of a renowned 18th-century astronomer.

Legend has it this spring formed at the spot where a medieval Swedish king was killed.

A large collection of ancient runestones decorates this university courtyard.

A rare rune stone dedicated to a woman.

The official meeting point for the oddly named governing assembly of ancient Sweden.

Uppsala's adorable feline sign celebrates a popular children's book set in the Swedish city.

A nightly tradition fills the streets of Flogsta with a collective scream.

This mysterious runestone embedded in a church wall is linked to the medieval cult of Saint Erik.

Ancient burial grounds of the wealthy.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

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.