Castries' harbour was protected by a system of 60 surrounding forts. Along the top of Morne Fortune, there are six military sites. Building work by the French started in 1768, and the British completed the work by 1890. They include Fort Charlotte (Old Morne Fortress), the Apostle's Battery (1888–1890), the Powder Magazine built by the French in the 1750s, Provost's Redoubt (1792) built as a lookout point, and the Combermere barracks.