Ground was broken on the Pentagon, a five-sided military headquarters built at breakneck speed in just 16 months on the eve of America's entry into World War II.

Franklin Roosevelt and Winston Churchill jointly announced the Atlantic Charter, a declaration of shared postwar goals including self-determination and disarmament.

SS and police units murdered over 23,000 Jewish men, women, and children near Kamianets-Podilskyi in occupied Ukraine, among the largest single massacres of the early Holocaust.

German forces severed Leningrad's last land route, beginning a siege that would starve nearly a million civilians over 872 days.

German occupation forces order Kyiv's Jews to assemble; over two days, nearly 34,000 are shot at the Babi Yar ravine.

After fourteen years of blasting granite in the Black Hills, sculptor Gutzon Borglum's monument to four presidents is declared finished.

Japan's Kido Butai carrier strike force departed Hitokappu Bay in the Kuril Islands under strict radio silence, bound for a surprise attack on Pearl Harbor.

British codebreakers at Bletchley Park achieved a critical breakthrough reading the German naval Enigma cipher, aiding the Battle of the Atlantic.

Tokyo instructed its Honolulu consulate to destroy most codes and ciphers, an intercepted signal that hinted at imminent attack but went dangerously unheeded.

President Franklin Roosevelt sent a personal telegram to Emperor Hirohito pleading for peace, hours before Japanese carriers launched their attack on Pearl Harbor.

Japanese carrier aircraft struck the U.S. Pacific Fleet at Pearl Harbor, killing 2,403 Americans and pulling the United States into World War II.

President Franklin D. Roosevelt asked Congress for a declaration of war against Japan following the attack on Pearl Harbor.

Japanese aircraft bombed U.S. bases in the Philippines hours after Pearl Harbor, opening a second front in the Pacific War.

Japanese forces invaded the American territory of Guam just three days after Pearl Harbor, overwhelming its small garrison of US Marines and Navy personnel in a matter of hours.