Línea Gustav
On the western side of the Apennines were two subsidiary lines, the Bernhardt Line in front of the main Gustav positions, and the Hitler Line some 8 kilometres (5 mi) to the rear. The Winter Line was fortified with gun pits, concrete bunkers, turreted machine-gun emplacements, barbed wire and minefields. It was the strongest of the German defensive lines south of Rome. About 15 German divisions were employed in the defence. It took the Allies from mid-November 1943 to June 1944 to fight through all the various elements of the Winter Line, including the well-known battles at Monte Cassino and Anzio.