Three people were killed and hundreds were injured when two bombs exploded near the finish line at the iconic Boston Marathon in April. The pressure cooker bombs were ignited as runners approached the finish line, leading to a chaotic scene on Boylston Street. Investigators say two brothers -- one of whom died in a shootout with police -- were behind the bombing. The attack resulted in an immediate re-evaluation of security at sports events and venues all over the world. Former NFL player Joe Andruzzi, pictured, was one of the many heroes that day as he carried an injured woman to safety.
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