LONDON, ENGLAND - APRIL 21: Runners stand in a silent tribute to the victims of the Boston Marathon bombings before the start of the London Marathon from Greenwich Park on April 21, 2013 in London, England. Thousands of runners are taking part - with some wearing black ribbons as a mark of respect to the Boston victims. Extra police are on duty as an estimated 500,000 people line the streets of the capital. (Photo by Peter Macdiarmid/Getty Images)
London Marathon pays tribute to Boston Marathon victims
Participants in the London Marathon, which was run less than a week after the Boston Marathon bombings, paid tribute to the victims.