Key Dates in World War 2

The 6-Year War That Killed 70–85 Million People

World War 2 (September 1, 1939 – September 2, 1945) was the deadliest conflict in human history. Estimates of total deaths range from 70 to 85 million, representing approximately 3–4% of the world's population in 1940. The war was fought across six continents (with active operations on five), involved 30 countries, and fundamentally reshuffled the global political order.

Here are 20 key dates, each with the specific numbers and context that make them meaningful rather than just names and years.

1939: The War Begins

September 1, 1939 — Germany invades Poland At 4:45 AM, Germany launched a combined arms assault with 1.5 million troops across multiple fronts. The Luftwaffe targeted Polish airfields; armored columns drove deep into Polish territory. This is the conventional start of World War 2 in Europe.

Britain and France declared war on Germany on September 3 (giving Germany 48 hours to withdraw — Hitler did not respond). This fulfilled the mutual defense guarantee they had given Poland in March.

September 17, 1939 — Soviet Union invades Poland from the east Two weeks after Germany's attack, the Soviet Union invaded from the east, pursuant to the secret Molotov-Ribbentrop Pact (August 1939) that had divided Eastern Europe into German and Soviet spheres. Poland was divided between the two powers by September 28.

1940: Fall of France, Battle of Britain

May 26 – June 4, 1940 — Dunkirk evacuation Germany's rapid advance through France trapped approximately 400,000 Allied troops at Dunkirk on the French coast. In 9 days, 861 vessels (including private fishing boats and pleasure craft) evacuated 338,226 soldiers — 198,000 British and 140,000 French — across the English Channel to Britain. The 62,000 who couldn't be evacuated were taken prisoner.

Churchill called it "a miracle of deliverance" but also warned: "Wars are not won by evacuations."

June 22, 1940 — France signs armistice with Germany France fell in 46 days — one of the fastest defeats of a major power in modern history. Northern France and the Atlantic coast fell under German occupation; a nominally independent government ("Vichy France") controlled the south. This left Britain as the only major Western power still fighting Germany.

July 10 – October 31, 1940 — Battle of Britain Germany needed air superiority over the English Channel to invade Britain. The RAF and Luftwaffe fought the first major battle decided entirely by air power. Germany's failure to achieve air superiority (losing approximately 1,733 aircraft vs. Britain's 915) forced Hitler to abandon the invasion plan. Churchill's famous line: "Never was so much owed by so many to so few."

1941: The War Goes Global

June 22, 1941 — Operation Barbarossa: Germany invades the Soviet Union The largest land invasion in history: 3.8 million Axis troops along a 2,900-kilometer front. Germany violated the Molotov-Ribbentrop Pact and drove deep into Soviet territory, capturing approximately 3.3 million Soviet prisoners in the first 6 months. The Eastern Front became the war's decisive theater — approximately 80% of German military casualties were suffered against the Soviet Union.

December 7, 1941 — Japan attacks Pearl Harbor At 7:55 AM Hawaii time, 353 Japanese aircraft attacked the US naval base at Pearl Harbor in two waves. 2,403 Americans were killed, 1,178 wounded; 4 battleships were sunk, 4 damaged; 169 aircraft destroyed. The US Pacific Fleet was damaged but not destroyed — the aircraft carriers were at sea and survived. Japan declared war on the US and Britain simultaneously; Germany and Italy declared war on the US four days later, making the conflict truly global.

1942–1943: Turning Points

June 4–7, 1942 — Battle of Midway Six months after Pearl Harbor, US codebreakers identified Japan's plan to attack Midway Atoll. The US Navy ambushed the Japanese fleet, sinking 4 Japanese fleet carriers (losing 1 US carrier) in 3 days. Japan never replaced these carriers and lost over 100 of its most experienced pilots. This was the turning point of the Pacific War — Japan went on the defensive from this point forward.

November 19, 1942 – February 2, 1943 — Battle of Stalingrad The Soviet counteroffensive (Operation Uranus) encircled Germany's 6th Army of approximately 300,000 troops in Stalingrad. After a brutal urban battle through the winter, 91,000 German survivors surrendered on February 2, 1943 — including 24 generals and Field Marshal Friedrich Paulus. Total casualties on both sides exceeded 2 million. This was the turning point on the Eastern Front.

November 8, 1942 — Allied landings in North Africa (Operation Torch) The first major US offensive of the war: 107,000 Allied troops landed in French Morocco and Algeria. Combined with British forces from Egypt, the Allies squeezed Axis forces in North Africa from both directions. By May 1943, approximately 275,000 Axis troops had surrendered — more than at Stalingrad.

1944: The Liberation Begins

June 6, 1944 — D-Day (Operation Overlord) The largest seaborne invasion in history. 156,115 Allied troops landed on 5 beaches in Normandy, France, supported by 11,590 aircraft and a naval fleet of approximately 5,000 ships. Casualties on the first day: approximately 10,000 Allied (4,414 confirmed dead) and 4,000–9,000 German. By the end of June, 850,000 Allied troops and 150,000 vehicles were in France.

The success of D-Day opened the Western Front and forced Germany to fight on three fronts simultaneously — East, West, and Italy.

August 25, 1944 — Liberation of Paris After 1,541 days of German occupation (June 1940 – August 1944), Paris was liberated by the French 2nd Armored Division and US 4th Infantry Division. Hitler had ordered Paris burned rather than surrendered; German military governor Dietrich von Choltitz refused the order and surrendered the city intact.

1945: The End

April 30, 1945 — Hitler dies in Berlin bunker As Soviet forces fought their way through Berlin street by street (at a cost of approximately 80,000 Soviet casualties in the Battle of Berlin alone), Hitler shot himself in his underground bunker. Germany surrendered unconditionally on May 8, 1945 — V-E Day (Victory in Europe Day).

August 6, 1945 — Atomic bomb dropped on Hiroshima The B-29 Enola Gay dropped a uranium bomb ("Little Boy") on Hiroshima, Japan. The explosion killed approximately 70,000–80,000 people immediately; total deaths from radiation and injuries reached approximately 90,000–140,000 by December 1945. Three days later, a plutonium bomb ("Fat Man") was dropped on Nagasaki, killing approximately 40,000–80,000.

September 2, 1945 — Japan surrenders, war ends Japanese Emperor Hirohito announced surrender on August 15 (V-J Day); the formal surrender was signed aboard the USS Missouri in Tokyo Bay on September 2, 1945, ending World War 2.

The Scale: Numbers That Contextualize the Conflict

• Total military deaths: approximately 21–25 million
• Total civilian deaths: approximately 50–55 million (including Holocaust victims)
• Holocaust victims: approximately 6 million Jewish people; approximately 11 million total if including all targeted groups
• Soviet Union deaths: approximately 27 million — by far the highest of any country, representing roughly 14% of the Soviet population
• Countries involved: 30 nations declared war at some point
• Duration: 2,193 days (September 1, 1939 – September 2, 1945)

The war's end created the world order of the following 75+ years: the United Nations (founded 1945), the division of Europe into Western and Soviet spheres, the establishment of Israel (1948), decolonization across Asia and Africa, and the beginning of the nuclear age — all direct consequences of the conflict.