A year after a pair of homemade pressure-cooker bombs killed three people and wounded more than 260 others at the Boston Marathon, runners and spectators began filtering in Monday morning at the starting line in Hopkinton amid tight security.
Boston Marathon
Boston Marathon Till T. Teuber of Hamburg, Germany, prepares himself before the 118th Boston Marathon Monday, April 21, 2014 in Boston. (AP Photo/Matt Rourke)
AP Photo/Matt Rourke
Andrea Murray lines up at the start of the Boston Marathon Monday morning. She ran with several friends from the D.C. area. Read her story here . (Courtesy Andrea Murray)
Courtesy Andrea Murray
Boston Marathon The 118th Boston Marathon gets underway as the mobility impaired runners leave the start line behind Monday, April 21, 2014 in Hopkinton, Mass. (AP Photo/Stephan Savoia)
AP Photo/Stephan Savoia
Boston Marathon A police officer walks past a Boston Strong banner as Wellesley College students affix the banner to the barricades before the start of the 118th Boston Marathon Monday, April 21, 2014 in Wellesley, Mass. (AP Photo/Mary Schwalm)
AP Photo/Mary Schwalm
Boston Marathon Race officials wire the electronics for the start line before the 118th Boston Marathon begins Monday, April 21, 2014 in Hopkinton, Mass. (AP Photo/Stephan Savoia)
AP Photo/Stephan Savoia
Dick Hoyt, Rick Hoyt Father and son Boston Marathon race team Dick Hoyt, right, and his son Rick Hoyt walk across the start line as they warm up before they run the 118th Boston Marathon Monday, April 21, 2014 in Hopkinton, Mass. (AP Photo/Stephan Savoia)
AP Photo/Stephan Savoia
Boston Marathon A member of the Massachusetts Department of Fire Services Haz-Mat crew affixes a device to the back of a street sign in front of Wellesley College before the start of the 118th Boston Marathon Monday, April 21, 2014 in Wellesley, Mass.. (AP Photo/Mary Schwalm)
AP Photo/Mary Schwalm
Boston Marathon Workers move security gates into position in front of Wellesley College in the early morning before the start of the 118th Boston Marathon Monday, April 21, 2014 in Wellesley, Mass. (AP Photo/Mary Schwalm)
AP Photo/Mary Schwalm
Boston Marathon Runners in the 118th Boston Marathon disembark a bus as they arrive near the start line Monday, April 21, 2014 in Hopkinton, Mass. (AP Photo/Stephan Savoia)
AP Photo/Stephan Savoia
Boston Marathon Runners cue to board busses ahead of the 118th Boston Marathon Monday, April 21, 2014 in Boston. (AP Photo/Matt Rourke)
AP Photo/Matt Rourke
Boston Marathon Runners make their way to load onto busses ahead of the 118th Boston Marathon Monday, April 21, 2014 in Boston. (AP Photo/Matt Rourke)
AP Photo/Matt Rourke
Boston Marathon Tears collect on Ron McCracken's of Dallas cheek as he pays his respects at a makeshift memorial honoring to the victims of the 2013 Boston Marathon bombings ahead of Monday's 118th Boston Marathon, Sunday, April 20, 2014, in Boston. McCracken's race last year was cut short due to bombings and Monday's race will mark his 14th year running in the Boston Marathon. (AP Photo/Matt Rourke)
AP Photo/Matt Rourke
Boston Marathon A visitor hangs a message on a tree at the "Dear Boston" exhibit at the Boston Public Library, Sunday, April 20, 2014, in Boston. The exhibit features a collection of items from the marathon bombing memorial. (AP Photo/Robert F. Bukaty)
AP Photo/Robert F. Bukaty
Boston Marathon Ron McCracken of Dallas pays his respects at a makeshift memorial honoring to the victims of the 2013 Boston Marathon bombings ahead of Monday's 118th Boston Marathon, Sunday, April 20, 2014, in Boston. McCracken's race last year was cut short due to bombings and Monday's race will mark his 14th year running in the Boston Marathon. The memorial is where the first of two explosions happened last year near the finish line. (AP Photo/Matt Rourke)
AP Photo/Matt Rourke
Boston Marathon A memorial to 2013 Boston Marathon bombing victim Martin Richard sits near the starting line of the 118th Boston Marathon Monday, April 21, 2014 in Boston. (AP Photo/Robert F. Bukaty)
AP Photo/Robert F. Bukaty