March 31, 1939 France and Great Britain guarantee the integrity of the borders of the Polish state.
September 3, 1939 Honoring their guarantee of Poland’s borders, Great Britain and France declare war on Germany.
September 17, 1939 The Soviet Union invades Poland from the east.
September 27–29, 1939 Warsaw surrenders on September 27. The Polish government flees into exile via Romania. Germany and the Soviet Union divide Poland between them.
July 10, 1940–October 31, 1940 The air war known as the Battle of Britain ends in defeat for Nazi Germany.
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.
May 30, 1942–May 1945 The British bomb Köln (Cologne), bringing the war home to Germany for the first time. Over the next three years Anglo-American bombing reduces urban Germany to rubble.
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.
October 23–24, 1942 British troops defeat the Germans and Italians at El Alamein in Egypt, sending the Axis forces in chaotic retreat across Libya to the eastern border of Tunisia.
November 23, 1942–February 2, 1943 Soviet troops counterattack, breaking through the Hungarian and Romanian lines northwest and southwest of Stalingrad and trapping the German Sixth Army in the city. Forbidden by Hitler to retreat or try to break out of the Soviet ring, the survivors of the Sixth Army surrender on January 30 and February 2, 1943.
July 10, 1943 US and British troops land on Sicily. By mid-August, the Allies control Sicily.
November 6, 1943 Soviet troops liberate Kiev.
June 4, 1944 Allied troops liberate Rome. Within six weeks, Anglo-American bombers could hit targets in eastern Germany for the first time.
June 22, 1944 The Soviets launch a massive offensive in eastern Byelorussia (Belarus), destroying the German Army Group Center and driving westward to the Vistula River across from Warsaw in central Poland by August 1.
July 25, 1944 Anglo-American forces break out of the Normandy beachhead and race eastward towards Paris.
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.
April 16, 1945 The Soviets launch their final offensive, encircling Berlin.
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 8, 1945 The Soviet Union declares war on Japan and invades Manchuria.
August 9, 1945 The United States drops an atomic bomb on Nagasaki.
AXIS POWERS
September 18, 1931 Japan invades Manchuria.
October 2, 1935–May 1936 Fascist Italy invades, conquers, and annexes Ethiopia.
November 25, 1936 Nazi Germany and Imperial Japan sign the Anti-Comintern Pact, directed against the Soviet Union and the international Communist movement.
July 7, 1937 Japan invades China, initiating World War II in the Pacific.
September 29, 1938 Germany, Italy, Great Britain, and France sign the Munich agreement which forces the Czechoslovak Republic to cede the Sudetenland, including the key Czechoslovak military defense positions, to Nazi Germany.
March 14–15, 1939 Under German pressure, the Slovaks declare their independence and form a Slovak Republic. The Germans occupy the rump Czech lands in violation of the Munich agreement, forming a Protectorate of Bohemia and Moravia.
April 7–15, 1939 Fascist Italy invades and annexes Albania.
August 23, 1939 Nazi Germany and the Soviet Union sign a nonaggression agreement and a secret codicil dividing eastern Europe into spheres of influence.
September 1, 1939 Germany invades Poland, initiating World War II in Europe.
April 9, 1940–June 9, 1940 Germany invades Denmark and Norway. Denmark surrenders on the day of the attack; Norway holds out until June 9.
May 10, 1940–June 22, 1940 Germany attacks western Europe—France and the neutral Low Countries. Luxembourg is occupied on May 10; the Netherlands surrenders on May 14; and Belgium surrenders on May 28. On June 22, France signs an armistice agreement by which the Germans occupy the northern half of the country and the entire Atlantic coastline. In southern France, a collaborationist regime with its capital in Vichy is established.
June 10, 1940 Italy enters the war. Italy invades southern France on June 21.
August 30, 1940 Second Vienna Award: Germany and Italy arbitrate a decision on the division of the disputed province of Transylvania between Romania and Hungary. The loss of northern Transylvania forces Romanian King Carol to abdicate in favor of his son, Michael, and brings to power a dictatorship under General Ion Antonescu.
September 13, 1940 The Italians invade British-controlled Egypt from Italian-controlled Libya.
September 27, 1940 Germany, Italy, and Japan sign the Tripartite Pact.
October 1940 Italy invades Greece from Albania on October 28.
November 1940 Slovakia (November 23), Hungary (November 20), and Romania (November 22) join the Axis.
February 1941 The Germans send the Afrika Korps to North Africa to reinforce the faltering Italians.
March 1, 1941 Bulgaria joins the Axis.
December 7, 1941 Japan bombs Pearl Harbor.
December 11–13, 1941 Nazi Germany and its Axis partners declare war on the United States.
September 8, 1943 The Badoglio government surrenders unconditionally to the Allies. The Germans immediately seize control of Rome and northern Italy, establishing a puppet Fascist regime under Mussolini, who is freed from imprisonment by German commandos on September 12.
September 12, 1944 Finland concludes an armistice with the Soviet Union, leaving the Axis partnership.
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.