Montgomery's 21st Army Group, including the US Ninth Army and the First Allied Airborne Army, crossed the Rhine in Operation Plunder in March 1945, two weeks after the US First Army had crossed the Rhine in the Battle of Remagen. By the end of the war, troops under Montgomery's command had taken part in the encirclement of the Ruhr Pocket, liberated the Netherlands, and captured much of north-west Germany. On 4 May 1945, Montgomery accepted the surrender of the German forces in north-western Europe at Lüneburg Heath, south of Hamburg, after the surrender of Berlin to the USSR on 2 May.