War crime, military necessity or tragic mistake? Deceits, blunders and lies led on 15 February 1944 Anglo-American planes to bomb the millennial abbey of Monte Cassino. This book documents, above all, the role of political leaders. Hitler was primarily to blame. He ordered the abolition of the neutral area promised to the Vatican and to stand not "inside" (as some British generals in particular believed) but "under the walls". In any case, on the Gustav Line, a decisive military advantage. Unlawful. Churchill in a telegram to General Alexander urged General Freyberg's attack. Reasons, results. Then he did not speak of Monte Cassino again, officially, for years. When he did... Roosevelt said: "Military necessity". Was it really so? For Rome, used militarily by the Germans, he sent the Pope an advice. Pius XII did not protest immediately and loudly: to protect Rome. From the Secret Archives a self-criticism emerges: even the abbey could have been saved. And the rescue of the Treasures boasted by the Germans? It resulted in the theft of many Neapolitan museums masterpieces. Göring's order, and Hitler knew it. But the monks hid the Treasure of San Gennaro, right on one of their trucks.