Up to 1975 this lovely recreational island in central Stockholm was anything but a nice place to visit or live in. It used to locate Långholmen Central Prison, one of the largest Swedish prison facilities.

The prison was built in 1874-1880 according to Wilhelm Theodor Anckarsvärd's drawings. The so-called Philadelphia model was applied (the cells arranged along the outer walls with a large corridor gallery) in combination with the Auburn system (dark night cells located at the center of the building and corridors facing the facade). The facility contained 200 day cells and 300 night cells, and was the only one of this kind  in Sweden.

Mohammed Beck Hadjetlaché, a journalist, writer, MI6 and Cheka agent was one of Långholmen’s most notable prisoners. And so was Carl Zeth "Zäta" Konstantin Höglund, a leading Swedish communist politician, anti-militarist, author and journalist. 

Långholmen prison left another mark in history as the place where the last execution in Sweden took place (https://reveal.world/story/1385 ).

The prison was closed down in 1975. Today it is a hotel, a museum and a conference center. In the museum you can learn about the history of this place, visit a prison cell and see how the prisoners lived back then. You can even stay at the prison hotel where the renovated cells offer all modern amenities and quite a unique atmosphere. 

Museum info: https://langholmen.com/en/langholmen-history/prison-museum/ 

Hotel: https://langholmen.com/en/hotell/