Pearl Harbor The Japanese bombed Pearl Harbor, Oahu, Hawaii on December 7, 1941 at 7:50 AM on a Sunday morning. There were over 3500 Navy, Army, and Marine troops killed. Four battle ships were sunk and many over military vessels were heavily damaged. The U.S. and Japan had not yet declared war and the U.S. military divisions were not on any type of wartime alert. In fact the Japanese diplomats were in Wash D.C. Conferring on possible ways to resolve their differences. Prior to the bombing the U.S. had broken Japan's secret code and interpreted Japan's messages about the bombing of Pearl Harbor. An inexperienced officer disregarded the message. The Japanese planes were concealed by a favorable weather front and not detected by radar. Many of the U.S. military troops were still sleeping early Sunday morning when Japan attacked. Immediately after the attack the U.S. declared war on Japan. My knowledge of Pearl Harbor bombing was learned from the U.S. Navy's tour of Pearl Harbor while I was in Oahu, Hawaii in 1995, and information I've read in the encyclopedia and heard from my grandfather. The viewpoint of my knowledge of Pearl Harbor is from the historical movie presented by the U.S. Navy with actual interviews of military officers and President Franklin d. Roosevelt as well as the actual bombing of Pearl Harbor filmed. What lead to Pearl Harbor's bombing was most importantly, a disregarded warning received by an inexperienced officer. Also, it was an early Sunday morning and most men were still sleeping and not on wartime alert so the Japanese could easily walk right in. At the time there was heavy cloud cover and it was an overcast morning. The heavy cloud cover made it so that the Japanese planes could not be spotted on the radar. After the Japanese bombed Pearl Harbor the U.S. declared war, which caused a large number of casualties and losses. If the U.S. had been better warned we would have been on alert and possibly ready for a counter attack.