The Fort de Fléron is one of twelve forts built around Liège, Belgium, in the late 19th century. The overall Fortified Position of Liège was a constituent part of the country's National Redoubt. Fort de Fléron was built between 1881 and 1891 according to the plans of General Henri Alexis Brialmont. Contrasting with the French forts built in the same era by Raymond Adolphe Séré de Rivières, the fort was built exclusively of unreinforced concrete, a new material, rather than masonry. The fort was heavily bombarded by German artillery in the Battle of Liège. Fléron was upgraded in the 1930s in an attempt to forestall or slow an attack from Germany. Located in the center of Fléron, the fort has been buried and is surrounded by apartments.