South-southwest of St. Petersburg, Florida, Fort De Soto Park is a park operated by Pinellas County on five offshore keys, or islands: Madelaine Key, St. Jean Key, St. Christopher Key, Bonne Fortune Key and the main island, Mullet Key. The keys are connected by either bridge or causeway. The island group is accessible by toll road from the mainland. Historically, the islands were used for military fortifications; remnants and a museum exhibit this history.