Axis collapse, Allied victory (1944–45)

[Peter]

Yalta Conference held in February 1945, with Winston Churchill, Franklin D. Rooseveltand  Joseph Stalin

On 16 December 1944, Germany attempted its last desperate measure for success on the Western Front by using most of its remaining reserves to launch a massive counter-offensive in the Ardennes to attempt to split the Western Allies, encircle large portions of Western Allied troops and capture their primary supply port at Antwerp to prompt a political settlement. By January, the offensive had been repulsed with no strategic objectives fulfilled. In Italy, the Western Allies remained stalemated at the German defensive line. In mid-January 1945, the Soviets and Poles attacked in Poland, pushing from the Vistula to the Oder river in Germany, and overran East Prussia. On 4 February, US, British, and Soviet leaders met for the Yalta Conference. They agreed on the occupation of post-war Germany, and on when the Soviet Union would join the war against Japan.

In February, the Soviets entered Silesia and Pomerania, while Western Allies entered western Germany and closed to the Rhine river. By March, the Western Allies crossed the Rhine north and south of the Ruhr, encircling the German Army Group B, while the Soviets advanced to Vienna. In early April, the Western Allies finally pushed forward in Italy and swept across western Germany, while Soviet and Polish forces stormed Berlin in late April. The American and Soviet forces linked up on Elbe river on 25 April. On 30 April 1945, the Reichstag was captured, signalling the military defeat of the Third Reich.

Several changes in leadership occurred during this period. On 12 April, President Roosevelt died and was succeeded by Harry Truman. Benito Mussolini was killed by Italian partisans on 28 April. Two days later, Hitler committed suicide, and was succeeded by Grand Admiral Karl Dönitz.

The German Reichstag after its capture by the Allies, 3 June 1945

German forces surrendered in Italy on 29 April. Total and unconditional surrender was signed on 7 May, to be effective by the end of 8 May. German Army Group Centre resisted in Prague until 11 May.

In the Pacific theatre, American forces accompanied by the forces of the Philippine Commonwealth advanced in the Philippines, clearing Leyte by the end of April 1945. They landed on Luzon in January 1945 and captured Manila in March following a battle which reduced the city to ruins. Fighting continued on Luzon, Mindanao, and other islands of the Philippines until the end of the war. On the night of 9–10 March, B-29 bombers of the US Army Air Forces struck Tokyo with incendiary bombs, which killed 100,000 people within a few hours. Over the next five months, American bombers firebombed 66 other Japanese cities, causing the destruction of untold numbers of buildings and the deaths of between 350,000–500,000 Japanese civilians.

Japanese foreign affairs minister Mamoru Shigemitsu signs the Japanese Instrument of Surrender on board the USSMissouri, 2 September 1945

In May 1945, Australian troops landed in Borneo, over-running the oilfields there. British, American, and Chinese forces defeated the Japanese in northern Burma in March, and the British pushed on to reach Rangoon by 3 May. Chinese forces started to counterattack in Battle of West Hunan that occurred between 6 April and 7 June 1945. American naval and amphibious forces also moved towards Japan, taking Iwo Jima by March, and Okinawa by the end of June. At the same time American bombers were destroying Japanese cities, American submarines cut off Japanese imports, drastically reducing Japan's ability to supply its overseas forces.

On 11 July, Allied leaders met in Potsdam, Germany. They confirmed earlier agreements about Germany, and reiterated the demand for unconditional surrender of all Japanese forces by Japan, specifically stating that "the alternative for Japan is prompt and utter destruction". During this conference, the United Kingdom held its general election, and Clement Attlee replaced Churchill as Prime Minister.

The Allies called for unconditional Japanese surrender in the Potsdam declaration of 27 July, but the Japanese government was internally divided on whether to make peace and did not respond. In early August the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. Like the Japanese cities previously bombed by American airmen, the US and its allies justified the atomic bombings as military necessity to avoid invading the Japanese home islands which would cost the lives of between 250,000–500,000 Allied troops and millions of Japanese troops and civilians. Between the two bombings, the Soviets, pursuant to the Yalta agreement, invaded Japanese-held Manchuria, and quickly defeated the Kwantung Army, which was the largest Japanese fighting force. The Red Army also captured Sakhalin Island and the Kuril Islands. On 15 August 1945, Japan surrendered, with the surrender documents finally signed aboard the deck of the American battleship USS Missouri on 2 September 1945, ending the war.