On Nobel Street, a miniature statue of Alfred Nobel.

A traveling Bronze Age sacrificial stone that was used to honor elves, fairies, and other woodland spirits.

This tree was once used to calculate the decrease of the Baltic Sea.

A collection of trees from various corners of the world call Stockholm University home.

This fantastic cave remained unexplored until 1948 when three schoolboys discovered a hidden entrance.

This 2,000-year-old stone maze is one of the oldest in the country, but its purpose is still a mystery.

Stone carvings record the Norse myth of Sigurd, providing a glimpse into Scandinavia's transition from paganism to Christianity.

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

A large collection of ancient runestones decorates this university courtyard.

Sweden's oldest street has not changed for nearly a millennium.

The suspected burial mound of legendary Viking Björn Ironside.

A golden egg-shaped sauna in the Arctic tundra.

This Viking Age memorial contains the oldest known image of a Täby resident.

"Only the dead get off at Kymlinge."

This railroad track was so secretive that it was omitted from all maps.

This stone obelisk is a relic of the 17th-century Swedish mile markers.

Not far from the busy city lie these remains of a time when the world was on fire.

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

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.

Although rarely used, there is still a hidden room for the royal family at the Stockholm central station.

This building, previously used as a courthouse, has an unusual geological feature in its basement.

A tombstone on the grounds of the royal castle marks the burial site of a Swedish king's beloved dog.

A water reservoir disguised as a castle stands atop a hill in a park in Stockholm city.

One of the world's oldest continuously operating meteorological stations sits on a hill in Stockholm.