On This Day 1941: "Surprise aggressive action at any moment is possible," read this U.S. warning about Japan - whose navy, at that very moment, was steaming, undetected, towards Hawaii 
The first meeting of the "Big Three" - Franklin D. Roosevelt, Winston Churchill and Josef Stalin - this day in 1943. Their conference in Iran planned the next stages of WWII - including setting a timetable for "Operation Overlord" - an invasion of Nazi-controlled France
A huge setback for the U.S. and its allies in Korea: China launched a surprise invasion with 300,000 troops, on this day in 1950. The top allied commander - Gen. Douglas MacArthur - thought that China would never enter the war and was blindsided
On This Day, 1963: On Thanksgiving Day, Jacqueline Kennedy, six days a widow, kneeled before her murdered husband's grave at Arlington
