Sitting atop Cap Diemont (the highest point in Quebec) "The Citadel" is still an active military base (i.e. Home to the 22nd Regiment). It is the oldest military installation in Canada and was part of the original fortifications of Quebec. Champlain had recognized the strategic importance of this promontory when he began construction of the original Fort St. Louis in 1608. The first part of of the fortified wall was completed in time for the Battle of Quebec in 1690. However, the French balked at constructing a full fort as being too costly. The British also felt a full fort would be too costly to build when they took over Quebec in 1759. This thinking began to change after the Americans attacked Montreal in 1775 and threatened Quebec in the War of 1812. Construction of the current star shaped fort began in 1820 and was completed in 1850. The design eliminated all blind spots along the walls, and grass was allowed to grow wild to helpful camouflage the fort. Following the Canadian Confederation of 1867, British forces left and Canada assumed responsibility for its own defense. Since 1920, the Citadel has housed the official residence of the Governor General of Canada and has been home to the Royal 22nd Regiment of Canada, the only totally French speaking force in Canada.

