Birger Jarls Torn (Birger Jarl's Tower), Stockholm

Birger Jarl's Tower (Birger Jarls Torn) is a historical defensive tower situated on the northwest corner of Riddarholmen, an islet in Gamla Stan, the old town of Stockholm. Despite being named after Birger Jarl, traditionally regarded as the founder of Stockholm, the tower was constructed several centuries later, around 1530, under the reign of King Gustav I of Sweden.

The tower was built to replace earlier timbered redoubts destroyed by fire in 1525. It is one of the few remnants of a 16th-century defensive system, alongside the southern tower of the Wrangel Palace. Originally connected by a wall, these structures were part of Gustav I's efforts to modernize and strengthen the capital's fortifications.

The construction of Birger Jarl's Tower utilized bricks from the demolished Saint Clare's Priory and other churches in the vicinity. The initial design featured a two-story building with a crenelated top and a thick cavity wall base near the waterfront, measuring almost 2.5 meters thick. In 1589-1590, the crenellation was converted into a third floor with a cone-shaped roof and white grouting added to the façade.

By the mid-17th century, the tower, then known as Rundelen ("the round tower"), was increasingly integrated with nearby structures. In the mid-18th century, significant alterations by Carl Hårleman included a fourth floor, a new roof with a gilt sphere, and windows. Throughout the 19th century, the tower and its adjacent buildings were frequently reconstructed for various uses, including a pawn shop and city archives. A comprehensive rebuild in the 1950s replaced old wooden joints with concrete and added barred windows, and a spiral staircase.

Before becoming the office of the Chancellor of Justice in 2007, the building was meticulously restored in 2006. This restoration involved removing some recent modifications and reinstating certain historical alterations, ensuring all new additions harmonized with the original structure. The top floor now serves as a round conference room, while the lower floors are intended for restaurant use to enhance Riddarholmen's appeal and accessibility to Stockholm residents.