This museum is housed in San Carlos Castle, constructed under Felipe III in 1610. The fort was used as a military prison until 1980, when it was rehabilitated and converted in a museum in order to expose the exhibition of the recently closed Artillery Park. Also with collections coming from the Army Museum, the Balearic Island Military service and private donations, the Castle opened as a museum in 1991. Apart from the visit of the castle itself, the collection exposed shows the military history of the Balearic Islands through various monographic rooms, in a historical journey spanning from antiquity to the present day. The original door of the castle, dating from 17th century, and its courtyard with examples of artillery, are the most interesting aspects of the visit.