Winston Churchill had long regarded southern Europe as the military weak spot of the continent (in World War I he had advocated the Dardanelles campaign, and during World War II he favoured the Balkans as an area of operations, for example in Greece in 1940). Calling Italy the "soft underbelly" of the Axis, Churchill had therefore advocated this invasion instead of a cross-channel invasion of occupied France. But Italy itself proved anything but a soft target: the mountainous terrain gave Axis forces excellent defensive positions, and it also partly negated the Allied advantage in motorized and mechanized units. The final Allied victory over the Axis in Italy did not come until the spring offensive of 1945, after Allied troops had breached the Gothic Line, leading to the surrender of German and RSI forces in Italy on 2 May shortly before Germany finally surrendered ending World War II in Europe on 8 May. Mussolini was captured and killed on 28 April 1945 by the Italian resistance while attempting to flee.