Stadion An der Alten Försterei (English: Stadium at the old forester's house) is the largest single-purpose football stadium in the German capital Berlin. It has been home to football club 1. FC Union Berlin and its forerunners since it was opened in 1920. The stadium's capacity was last redeveloped in 2009 and expanded in 2013. Some of the redevelopment work was carried out by over 2,300 Union Berlin supporters volunteering their services. During league matches the arena features a total capacity of 22,012 including 3,617 seats whilst the rest of the ground remains terracing.