On June 6, 1944 (known as D-Day), the Western Allies invaded northern France and, after reassigning several Allied divisions from Italy, southern France;^[1] by August 25, Paris was liberated.^[2] During the latter part of the year, the Western Allies continued to push back German forces in western Europe, and in Italy ran into the last major defensive line.

On June 22, the Soviets launched a strategic offensive in Belarus (known as "Operation Bagration") that resulted in the almost complete destruction of the German Army Group Centre.^[3] Soon after that, another Soviet major strategic offensive forced the German troops from Ukraine and Eastern Poland. Major assaults against Finland and Romania resulted in great successes, with Bulgaria, Romania and Finland signing armistices with the Soviet Union,^[4] and prompted Polish resistance forces to initiate several uprisings in Poland, though the largest of these, in Warsaw, was conducted without Soviet assistance and put down by German forces.^[5] On October, the Soviets launched a massive assault against Germany occupied Hungary that lasted until the fall of Budapest in February 1945.^[6]

By the start of July, Commonwealth forces in Southeast Asia had repelled the Japanese sieges in Assam, pushing the Japanese back to the Chindwin River^[7] while the Chinese captured Myitkyina. In China, the Japanese were having greater successes, having finally captured Changsha in mid-June and the city of Hengyang by early August.^[8] Soon after, they further invaded the province of Guangxi, winning major engagements against Chinese forces at Guilin and Liuzhou by the end of November^[9] and successfully linking up their forces in China and Indochina by the middle of December.^[10]

In the Pacific, American forces continued to press back the Japanese perimeter. In the middle of June, 1944, they began their offensive against the Mariana and Palau islands, scoring a decisive victory against Japanese forces in the Philippine Sea within a few days. In late October, American forces invaded the Filipino island of Leyte; soon after, Allied naval forces scored another large victory against the Japanese in the Leyte Gulf.^[11]