The duke of Wellington had this partially star-shaped fortress built at the east end of the city walls in anticipation of renewed American attacks after the War of 1812. Some remnants of earlier French military structures were incorporated into the Citadel, including a 1750 magazine. Dug into the Plains of Abraham, the fort has a low profile that keeps it all but invisible until walkers are actually upon it. Never having exchanged fire with an invader, it continues its vigil from the tip of Cap Diamant. British construction of the fortress, now a national historic site, was begun in 1820 and took 30 years to complete. As events unfolded, it proved to be an exercise in obsolescence. Since 1920, it has been home to Québec's Royal 22e Régiment, the only fully Francophone unit in Canada's armed forces. That makes it the largest fortified group of buildings still occupied by troops in North America. As part of a guided tour only, the public may visit the Citadel and its 25 buildings, including the small regimental museums in the former powder house and prison. Despite a couple of spectacular overlooks, the length of the tour and the dry narration are likely to test the patience of younger visitors and the legs of many older people. In those cases, it might be better to attend the ceremonies of the changing of the guard or beating the retreat (see times and dates for those events in the information listing below). Walk or drive up the Côte de la Citadelle (entrance near the St-Louis Gate); there are many parking spaces inside the walls.