As two bomb explosions ripped through the Boston Marathon on Monday, individuals able to help rushed to the scene to assist the victims.
One of those brave people included Carlos Arredondo, who was watching the race to support a runner who was running the marathon in honor of his son, Lance Cpl. Alexander S. Arredondo, who was killed in Iraq in 2004.
Watch Arredondo and some of the other heroes in action. [Warning: Graphic images]