Thousands of runners are preparing to take part in an emotional Boston Marathon amid unprecedented security.In last year’s race two bombs exploded near the finish line, killing three people and wounding more than 260.
But the attack has not deterred runners from Monday’s event. More than 36,000 will start – 9,000 more than normal.
Half a million spectators are expected to turn out. They will pass through checkpoints and will not be allowed to bring rucksacks – only clear bags.
The BBC’s Nick Bryant in Boston says that never before has the marathon been run amid so many layers of security.
Protecting the 26.2 mile route has involved a massive mobilisation of law enforcement agencies, including police units, bomb squads and Swat teams from other states.
The Boston police department has erected 8,000 steel barricades, 1,200 more than last year.
Massachusetts Governor Deval Patrick told CBS television on Sunday that the added security measures would assure a “very safe” atmosphere.
Runners and their families posed at the finish line on Sunday, determined to take part in the event.
Canadian runner Mark Rush told Reuters: “The bad guys aren’t gonna take this race away from us and all the people that get involved in it. It’s good to be back doing it again.”
British participant Mark Hazelhurst said: “I think everybody wants to come to run and to celebrate running and celebrate the city here. I think that’s a real difference from last year.”
Many people in the city have been wearing “Boston Strong” T-shirts.
Last year’s winner, Lelisa Desisa, returns to compete again. He has met several victims of the blast, calling them “an inspiration”.
The event will begin with a moment’s silence at the start line at 08:45 (12:45 GMT).
Bombing suspect Dzhokhar Tsarnaev, 20, is due to stand trial in November. He has pleaded not guilty to 30 charges, including 17 that carry the death penalty.
Prosecutors allege that he set off two pressure cooker bombs with his older brother Tamerlan, 26, who later died in a police shoot-out.