Hiroshima on Saturday remembered the atomic bombing 77 years ago. Attendees including government leaders and diplomats observed a moment of silence with the sound of a peace bell at 8:15 a.m., the time when the U.S. B-29 dropped the bomb on the city. Hiroshima Mayor Kazumi Matsui, in his peace declaration, urged the world not to repeat the mistakes that destroyed his city nearly eight decades ago.