The Citadelle of Quebec is a military installation and official residence of both the Monarch of Canada and the Governor General of Canada located atop Cap Diamant, adjoining the Plains of Abraham in Quebec City, Quebec, Canada. This citadel is part of the fortifications of Quebec City. The city of Quebec is the only one in North America with Campeche in Mexico that is still surrounded by fortifications. The Citadelle is a National Historic Site of Canada, and also forms part of the Fortifications of Québec National Historic Site of Canada. The fortress is located within the "Historic District of Old Québec", which was designated a World Heritage Site in 1985.