An injured man is loaded into an ambulance after two bombs went off near the finish line of the Boston Marathon on April 15, 2013. Three people were killed and at least 264 were injured.
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A man comforts a victim on the sidewalk at the scene of the first explosion.
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The second explosion goes off near the finish line.
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The first explosion knocked down 78-year-old runner Bill Iffrig at the finish line. He got up a few minutes later and finished the race.
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A runner embraces another woman on the marathon route near Kenmore Square.
A victim of the first explosion is helped on the sidewalk of Boylston Street.
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An injured person is taken away from the scene in a wheelchair.
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A woman kneels and prays at near the finish line.
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People run down Exeter Street after the blasts.
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The explosions occurred around 2:45 p.m., about an hour after the first of the race's nearly 27,000 runners had crossed the finish line.
courtesy Dan Lampariello
Victims lie on the ground at the scene of the first explosion.
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A couple runs from the scene pushing a stroller.
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A runner reacts near Kenmore Square after the explosions.
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A man's blood-stained feet hang outside an ambulance.
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A bystander who was injured in the first explosion is wheeled across the finish line while receiving medical attention from rescue workers.
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Carlos Arredondo was at the race handing out American flags to spectators. After the blasts, he helped emergency responders and is credited with helping a man survive serious leg wounds.
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The second explosion goes off near the finish line.
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Police look at blown-out windows. The bombs shook buildings, witnesses said, sending people to seek shelter under tables.
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Unclaimed runners' bags fill an area near the marathon finish.
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Women desperate to hear from loved ones are unable to get close to the site of the attack.
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Police and runners stand near Kenmore Square after the attack.
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Runners gather near Kenmore Square after the explosions.
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An EMT worker is transferred to an ambulance outside a medical tent in Copley Square.
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A SWAT team arrives on the scene.
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A runner sits near Kenmore Square after the attack.
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Runners who had not yet finished the race are stopped after the explosions.
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Victims are helped at the scene of the first explosion.
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A man in tears is helped at the scene on Boylston Street.
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Passersby put pressure on a victim's leg to try to stop the bleeding.
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Massachusetts State Police guard an area near Kenmore Square.
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Bystanders embrace near the finish line.
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Police officers gather on Newbury Street.
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Women and children are escorted away from the scene.
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Bomb squad officials check a possible suspicious device near the scene of the blasts.
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A woman is comforted after the blasts.
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Two injured women are taken away on stretchers.
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An injured woman is loaded into an ambulance.
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First responders load injured people into an ambulance.
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An injured man is prepared to be moved from a stretcher to an ambulance.
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An injured woman is placed on a stretcher.
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A runner is comforted following the attack.
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The Cambridge Police Department's bomb squad investigates unattended personal items left behind after the explosions.
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Bystanders check their mobile devices for news of the explosions.
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A member of the bomb squad investigates a suspicious item on the road near Kenmore Square.
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A runner in a wheelchair is taken from a triage tent after the explosions went off.
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People comfort each near the site of the blasts.
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Racers and race officials stand by after the explosions.
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Emergency personnel respond to the scene.
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Police and emergency crews tend to victims.
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An injured woman is carried away on a stretcher.
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A man lies on the ground after the incident.
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Officials watch as the first explosion goes off on Boylston Street.
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Spectators leave the bleachers after the explosions.