The Allied invasion of Southern Italy in September 1943 led to one of the most controversial campaigns of World War II. To prevent invaders from reaching Rome, the Germans constructed a chain of fortifications across Italy. Integral to this was the mountain-top monastery of Monte Cassino. Monte Cassino and its surroundings would be the site of thousands of Allied and Germans casualties in four battles in 1944. The monastery was bombed by the Allies in the mistaken belief that German troops were occupying it. After this bombing that destroyed much of the monastery, elite German paratroopers occupied the rubble and it took several months and several thousand lives to dislodge them. Brigadier John MacFarlane explores the impact of these battles.