The impregnable fortress of Fort Royal was built between 1624 and 1627 with the aim of preventing sea access to Cannes, and at the end of the seventeenth century the fort became a government prison, and among the prisoners held within it was the famous, unidentified man in the iron mask who was held for 11 years from 1687 to The year 1698. This historical fortress also houses a museum containing antiquities of Roman pottery.