Battle of Monte Cassino, Italy in World War II. Allied shelling reduces town to ...HD Stock...

This multi-faceted battle marked one of the longest and bloodiest engagements of the Italian campaign during World War II. After attempts to overcome the Germans in the Liri Valley and at Anzio ended in stalemate, the Allies struggled to capture the western anchor of the Gustav Line and the Roman Catholic abbey of Monte Cassino.
The bombing mission in the morning of 15 February 1944 involved 142 Boeing B-17 Flying Fortress heavy bombers followed by 47 North American B-25 Mitchell and 40 Martin B-26 Marauder medium bombers. In all they dropped 1,150 tons of high explosives and incendiary bombs on the abbey, reducing the entire top of Monte Cassino to a smoking mass of rubble. Between bomb runs, the II Corps artillery pounded the mountain. Many Allied soldiers and war correspondents cheered as they observed the spectacle. Eaker and Devers watched; Juin was heard to remark "... no, they’ll never get anywhere this way." Clark and Gruenther refused to be on the scene and stayed at their headquarters. That same afternoon and the next day an aggressive follow-up of artillery and a raid by 59 fighter bombers wreaked further destruction. The German positions on Point 593 above and behind the monastery were untouched.

Damningly, the air raid had not been coordinated with ground commands and an immediate infantry follow-up failed to materialize. Its timing had been driven by the Air Force regarding it as a separate operation, considering the weather and requirements on other fronts and theaters without reference to ground forces. Many of the troops had only taken over their positions from U.S. II Corps two days previously and besides the difficulties in the mountains, preparations in the valley had also been held up by difficulties in supplying the newly installed troops with sufficient material for a full-scale assault because of incessantly foul weather, flooding and waterlogged ground. As a result, Indian troops on the Snake's Head were taken by surprise,while the New Zealand Corps was two days away from being ready to launch their main assault.
Pope Pius XII was silent after the bombing; however, his Cardinal Secretary of State, Luigi Maglione, bluntly stated to the senior U.S. diplomat to the Vatican, Harold Tittmann, that the bombing was "a colossal blunder . . . a piece of a gross stupidity."
https://en.wikipedia.org/wiki/Battle_of_Monte_Cassino
http://www.history.com/topics/world-war-ii/battles-of-monte-cassino