Castel d'Appio is a medieval castle built by the Genoese in the 13th century. It occupies the site of an Roman militarity camp (castrum) and early Ligurian defense post. The castle lost its purpose in the 18th century and was partially demolished. Today parts of walls and towers remain.
The Citadelle of Quebec is an active military installation and official residence of both the Canadian monarch and the Governor General of Canada. It is located atop Cap Diamant, adjoining the Plains of Abraham in Quebec City. The citadel is the oldest military building in Canada, and forms part of the fortifications of Quebec City, which is one of only two cities in North America still surrounded by fortifications, the other being Campeche, Mexico.
The first fortifications in Quebec were built by the Governor General of New France Louis de Buade, and completed just in time for the Battle of Quebec in 1690.
After the British conquest in the second half of the 18th century, the problem of Quebec City's defences grew more acute.