and the Rhine. German forces in Italy were withdrawing north, as they were pressed by the U.S. and Commonwealth forces as part of the Spring Offensive to advance across the Po and into the foothills of the Alps. Hitler retreated to his Führerbunker in Berlin on 16 January 1945. It was clear to the Nazi leadership that the battle for Berlin would be the final battle of the war in Europe. Some 325,000 soldiers of Germany's Army Group B were surrounded and captured in the Ruhr Pocket on 18 April, leaving the path open for U.S. forces to reach Berlin. By 11 April, the Americans crossed the Elbe, to the west of the city. On 16 April, Soviet forces to the east crossed the Oder and commenced the battle for the Seelow Heights, the last major defensive line protecting Berlin on that side. By 19 April, the Germans were in full retreat from Seelow Heights, leaving no front line. Berlin was bombarded by Soviet artillery for the first time on 20 April, Hitler's birthday. By the evening of 21 April, Red Army tanks reached the outskirts of the city. On 21 April, Hitler ordered a special detachment commanded by SS-General Felix Steiner to counterattack the Soviets. At the next day's afternoon situation conference, Hitler suffered a nervous collapse when he was informed that these orders had not been obeyed. He launched into a tirade against his generals, calling them treacherous and incompetent, culminating in a declarationfor the first timethat the war was lost. Hitler announced that he would stay in Berlin until the end and then shoot himself. Later that day, he asked SS physician Werner Haase about the most reliable method of suicide. Haase suggested the "pistol-and-poison method" of combining a dose of cyanide with a gunshot to the head. Luftwaffe chief Hermann Göring learned about Hitler's admission of defeat and declaration of his intended suicide and sent a telegram to Hitler, asking for permission to take over the leadership of the Reich in accordance with Hitler's 1941 decree naming him as his successor. Hitler's secretary Martin Bormann convinced Hitler that the letter from Göring was an attempt to overthrow the dictator. In response, Hitler informed Göring that he would be executed unless he resigned all of his posts. Later that day, he sacked Göring from all of his offices and ordered his arrest. Hitler also ordered his chief