The Cittadella, among the most important examples of military architecture from the Italian 18th century, is located north-west of Alessandria and is separated from the city by the river Tanaro. After it was ceded to the Savoy in 1713, Alessandria was fortified to the point of becoming one of the most relevant strategic spots in Piemonte. The fortress, designed by the Italian military architect Ignazio Bertola and built between 1732 and 1808, was the setting of several key moments in the history of both Italy and Europe. During Napoleonic times, it was one of the most important fortresses of the Empire; during the Italian Unification, it was a symbol of the revolutionary movements in favour of the Constitution. Spreading over 74 hectares, it is a perfect example of a modern-type fortification with six bastions.
The slow degradation of the monument started in 2007, when its military use ended. The most imminent threat is the proliferation of a very invasive weed, the roots of which are seriously undermining the walls and threatening the integrity of the fortification.