On December 7, 1941, Japan attacked US' Pearl Harbour, leading to deaths of over 3,500 American troops and civilians. Japan's 183 planes bombed the Pacific fleet for 30 minutes at 7:55 am. After a 15-minute lull, 170 Japanese planes launched another attack. Hours later, US joined World War II. Donald Trump joked about the attack with Japan PM Sanae Takaichi.