The scene after the two explosions occurred.
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Workers aid injured people at the finish line.
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Women react as they walk from the area where there was an explosion.
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Medical workers aid injured people.
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Medical workers aid injured people at the finish line.
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Medical workers aid injured people.
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Runners who were diverted from the race course walk on the Commonwealth Mall two blocks from the site of the explosion.
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A Boston police officer wheels in injured boy down Boylston Street as medical workers carry an injured runner.
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Medical workers aid injured people at the finish line.
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Medical workers aid an injured person.
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Police monitor New York's Times Square during an increase in security following the Boston explosion.
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People assist an injured man.
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Medical workers aid injured people.
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One of the blast sites on Boylston Street near the finish line.
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A firefighter tends to an injured man.
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President Barack Obama leaves the podium after speaking in the James Brady Press Briefing Room at the White House following the explosions.
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Medical workers aid an injured woman.
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Blood from victims covers the sidewalk on Boylston Street.
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In this image from video provided by WBZ TV, spectators and runners run from what was described as twin explosions that shook the finish line of the Boston Marathon.
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Medical workers aid an injured woman at the finish line.
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Medical workers aid an injured man.
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