Londoners marked the third anniversary Monday of suicide bomb attacks that killed 52 bus and subway passengers. Commuters and survivors stood silently as Mayor Boris Johnson and government officials laid flowers outside King's Cross train and subway station at 8:50 a.m. (0750GMT), three years after the rush-hour attacks of July 7, 2005. The bombers, British Muslims inspired by al-Qaida, set off from King's Cross that morning and blew themselves up aboard three subway trains and a bus in the deadliest attack on London since World War II. As well as the dead, more than 700 people were injured. Johnson laid a memorial card that said: "We honor the memory of those who died on 7/7 2005, we salute the courage of those who were injured and our thoughts and prayers are with all victims and their families." Relatives of some of the victims held private ceremonies at the sites of the subway explosions at Russell Square, Aldgate and Edgware Road stations, and in Tavistock Square, where the bus exploded.