This fort is arguably the best preserved in Sweden. Famous for harboring and protecting the Danes during the war between 1717 and 1917, the fort was attacked again and again. Today, it is one of the most popular boat tours in Gothenburg. The trip includes a guided historical tour, as well as being very informative. The boat trip takes about 30 minutes. Also on the island there is a café, a small handicraft shop, winding paths, and beautiful surroundings.