In the summer this is a haven in the middle of the city. It is a public garden where I like to go and relax in the grass under a blooming tree. There is also a cafe and a shop here. Before you leave you should buy a bouqee of flowers (you pick yourself in the garden!).
Great area on the shore of Kungsholmen in Stockholm, just a couple of stops from the city centre on the tube . Ideal for a swim or summer (or winter for that matter) barbecue with friends.