June 10, 1940
Italy enters the war. Italy invades southern France on June 21.
July 10, 1940–October 31, 1940
The air war known as the Battle of Britain ends in defeat for Nazi Germany.
October 1940
Italy invades Greece from Albania on October 28.
December 7, 1941
Japan bombs Pearl Harbor.
December 8, 1941
The United States declares war on Japan, entering World War II. Japanese troops land in the Philippines, French Indochina (Vietnam, Laos, Cambodia), and British Singapore. By April 1942, the Philippines, Indochina, and Singapore are under Japanese occupation.
December 11–13, 1941
Nazi Germany and its Axis partners declare war on the United States.
June 1942
British and US navies halt the Japanese naval advance in the central Pacific at Midway.
August–November 1942
US troops halt the Japanese island-hopping advance towards Australia at Guadalcanal in the Solomon Islands.
November 8, 1942
US and British troops land at several points on the beaches of Algeria and Morocco in French North Africa. The failure of the Vichy French troops to defend against the invasion enables the Allies to move swiftly to the western border of Tunisia, and triggers the German occupation of southern France on November 11.
September 9, 1943
Allied troops land on the beaches of Salerno near Naples.
June 4, 1944
Allied troops liberate Rome. Within six weeks, Anglo-American bombers could hit targets in eastern Germany for the first time.
June 6, 1944
British and US troops successfully land on the Normandy beaches of France, opening a “Second Front” against the Germans.
August 20–25, 1944
Allied troops reach Paris. On August 25, Free French forces, supported by Allied troops, enter the French capital. By September, the Allies reach the German border; by December, virtually all of France, most of Belgium, and part of the southern Netherlands are liberated.
October 20, 1944
US troops land in the Philippines.
December 16, 1944
The Germans launch a final offensive in the west, known as the Battle of the Bulge, in an attempt to re-conquer Belgium and split the Allied forces along the German border. By January 1, 1945, the Germans are in retreat.

April 30, 1945
Hitler commits suicide.

May 7, 1945
Germany surrenders to the western Allies.

May 9, 1945
Germany surrenders to the Soviets.
May 1945
Allied troops conquer Okinawa, the last island stop before the Japanese islands.
August 6, 1945
The United States drops an atomic bomb on Hiroshima.
August 9, 1945
The United States drops an atomic bomb on Nagasaki.
September 2, 1945
Having agreed in principle to unconditional surrender on August 14, 1945, Japan formally surrenders, ending World War II.