About 36,000 runners registered for the 118th running of the Boston Marathon.
More than one million spectators were expected to cheer on runners in the first Marathon since the bombings that killed three people and wounded more than 260 others.
Thousands of law enforcement officers lined the route as officials tightened security for the 2014 race. Boston Mayor Marty Walsh said authorities put together a very good plan to make sure people were going to have a great experience, but yet feel safe.