The ancient fortress Ismantorp, on the island of Öland, is an archaeological enigma as well as a popular place to visit.
Ismanstorps well-preserved walls distinguish the fortress, as do the central building's unusual location on a ground elevation, the 88 visible house foundations and the nine gates.
Houses were built on practically all space within the fortress-walls. Ruins of large and small houses can be seen along a network of streets and alleys that bind all parts of the fortress to the gates in the fortified wall. There is a square in the middle of the fortress area, and the town planning is reminiscent of a medieval community.