British military engineers built fortifications at Quebec from the end of the 18th Century.
The main threat to Quebec City at that time was seen to be from the Americans. Two attempts of American invasion in 1775-1776 and 1812-1813 had been unsuccessful, but there was the fear of a new war. The Citadel of Quebec was planned and built in 1821-1930.
The Chief engineer of the project was Elias Walker Durnford, a colonel in the Royal Engineers. The design he used was influenced by such engineers as Gother Mann and Ralph Bruyere. Besides, the concept of the famous French military engineer Vauban who developed the concept of bastions. The fortress was built in a shape of a star of limestone from Cap-Rouge.
The blocks were transported by boat and by ox-cart. Then they were winched up a 360-feet ramp from the river using horse-power. According to the records, in 1828 there were as many as 873 craftsmen and day laborers working on the site. The Citadel was in fact never tested, but it served as a deterrent.
The British withdrew their garrison in 1871, and the Citadel was taken over by the government of Canada. Since 1920, the fortress has been the home for the French Canadian Royal Regiment the Royal 22. The complex serves as well as the official residence of Canada's Governor-General when she or he visits Quebec City.
The Citadel. View from the Observatoire de Québec. Photo : Provincequebec.com