During major works, Vauban pushed back the course of the river, La Savoureuse, to increase the surface area of the city, which he enclosed in a pentagon of fortifications. The medieval and classical old town surrounded by ramparts is just the ticket for a pleasant stroll - head for the Place d'Armes or Place de la République. In the late 19C, further to significant population growth, the city spread out; neighbourhoods with wide streets and vast squares, built in line with the Haussmann model, saw the light of day.