The Thiers wall was the last of the defensive walls of Paris. It was an enclosure constructed between 1841 and 1844 under a law enacted by the government of the French prime minister, Adolphe Thiers. It covered 7,802 hectares (19,280 acres), along the "boulevards des Maréchaux" (Boulevards of the Marshals) of today. A sloping area outside the wall, called a glacis, extended outward from the Thiers wall to the location of today's Boulevard Périphérique. The wall was demolished in stages between 1919 and 1929.