The Falaise Pocket or Battle of the Falaise Pocket (12–21 August 1944) was the decisive engagement of the Battle of Normandy in the Second World War. A pocket was formed around Falaise, Calvados, in which the German Army Group B, with the 7th Army and the Fifth Panzer Army (formerly Panzergruppe West) were encircled by the Western Allies. The battle is also referred to as the Battle of the Falaise Gap, after the corridor which the Germans sought to maintain to allow their escape and is sometimes referred to as the Chambois Pocket, the Falaise-Chambois Pocket, the Argentan–Falaise Pocket or the Trun–Chambois Gap. The battle resulted in the destruction of most of Army Group B west of the Seine river, which opened the way to Paris and the German border for the Allied armies.