On Dec. 7, 1941, Japanese invaded Pearl Harbor, Hawaii, 71 years ago. In an hour and a half, the Japanese sank or damaged 21 American warships, killed 2,390 people and destroyed or damaged 320 planes in the attack. President Barack Obama on Thursday Dec. 6, 2012 issued a proclamation declaring Dec. 7 a day of remembrance in honor of the 2,400 Americans who died at Pearl Harbor. He urged federal agencies, organizations and others to fly their flags at half-staff.