Fact: The invasion used blitzkrieg ("lightning war") tactics—coordinated air strikes, tanks, and infantry. Fun fact: The Soviet Union invaded Poland from the east on September 17, 1939, as part of the secret Molotov-Ribbentrop Pact with Nazi Germany. Poland was defeated in 6 weeks. Britain and France declared war on September 3, but no major combat occurred until spring 1940 (the "Phoney War").

Fact: President Franklin D. Roosevelt called it "a date which will live in infamy." Fun fact: The attack destroyed 188 US aircraft and 8 battleships, but aircraft carriers (the future key naval weapon) were at sea. 1,177 crew died on USS Arizona alone. Germany and Italy declared war on the US on December 11, 1941. The US declared war on Japan on December 8. Isolationism ended overnight—4 million Americans volunteered in 1942.

Fact: Operation Overlord involved 6,939 vessels and 11,590 aircraft. Fun fact: Omaha Beach was the deadliest with 2,400 American casualties. The Allies suffered approximately 10,000 total casualties (killed, wounded, missing) on D-Day, with 4,414 confirmed dead. German Field Marshal Rommel was home celebrating his wife's birthday. By June 11, 326,000 troops, 54,000 vehicles, and 104,000 tons of supplies had landed. Paris was liberated on August 25, 1944.

Fact: The "Final Solution" used extermination camps including Auschwitz-Birkenau (1.1 million killed), Treblinka (800,000), and Sobibor (250,000). Fun fact: The largest single massacre was at Babi Yar (September 1941), where 33,771 Jews were shot in two days in a Ukrainian ravine. Only about 200,000 of Europe's 9 million pre-war Jews survived in German-occupied territory. Anne Frank's diary, written while hiding in Amsterdam, has sold over 30 million copies worldwide.

Fact: The bombs "Little Boy" (uranium) and "Fat Man" (plutonium) had yields of 15 and 21 kilotons of TNT. Fun fact: The original target list included Kyoto, but Secretary of War Henry Stimson (who had honeymooned there) removed it for cultural reasons. The bombings remain the only use of nuclear weapons in warfare. Japan formally surrendered on September 2, 1945, aboard the USS Missouri. Total WWII deaths from all causes: 70-85 million (3% of world population).

Fact: The 5-month battle ended with the surrender of German Field Marshal Paulus's Sixth Army (91,000 soldiers). Fun fact: Only 6,000 German survivors returned home, some not until 1955. Soviet snipers, including Vasily Zaytsev (242 confirmed kills), used the city's rubble for cover. The German soldier's daily ration fell to 1 slice of bread and 2 tablespoons of flour per day. Hitler promoted Paulus to Field Marshal (expecting suicide), but Paulus surrendered.

Fact: The Battle of Britain was an air campaign: Germany's Luftwaffe vs. Britain's Royal Air Force (RAF). Fun fact: Winston Churchill famously said, "Never in the field of human conflict was so much owed by so many to so few" (the "Few" were 2,936 RAF pilots). The battle lasted July-October 1940. Germany lost 1,733 aircraft, Britain 915. Hitler postponed and eventually canceled Operation Sea Lion (the invasion of Britain). This was Nazi Germany's first major defeat.

Fact: Approximately 10,000-20,000 died on the march or in prison camps. Fun fact: Japanese commanders were later tried for war crimes; General Masaharu Homma was executed in 1946. Survivors endured beheadings, bayonetings, and shooting of anyone who fell. The march lasted 6-12 days. After the war, the Japanese emperor Hirohito was not prosecuted due to US political calculations. The Bataan Death March is commemorated annually by US and Filipino veterans.

Fact: Led by J. Robert Oppenheimer, the project produced Trinity (first test) on July 16, 1945. Fun fact: Oak Ridge, Tennessee (population 75,000), didn't appear on maps. Soviet spies (including Klaus Fuchs) infiltrated the project, accelerating Stalin's bomb program. The German atomic program failed partly because Heisenberg miscalculated critical mass. Oppenheimer quoted the Bhagavad Gita after Trinity: "Now I am become Death, the destroyer of worlds."

Fact: The UN Charter was signed in San Francisco on June 26, 1945, effective October 24. Fun fact: The term "United Nations" was first used by President Roosevelt in 1942. The UN has 193 member states today. The Security Council's veto power (each permanent member can block any resolution) reflects post-WWII power realities. The UN has 15 specialized agencies, including WHO, UNESCO, and the World Bank. The UN budget is about $3 billion annually.