The event was disrupted and largely overshadowed by a terrorist attack in which two consecutive explosions on the sidewalk, near the finish line, killed three spectators and injured hundreds of others.

This area is filled with a 'tunnel' of young women from the nearby Wellesley College who request kisses from runners, a tradition that has been in place for more than 100 years.

[2][5] The course is mostly downhill to the end, and passes through Boston College before entering Cleveland Circle then Kenmore Square where there are many spectators.

[7] Reigning wheelchair champions Joshua Cassidy and Shirley Reilly returned to defend their titles in their respective categories.

[10] After 26 seconds of silence to honor the victims of the Sandy Hook Elementary School shooting, the marathon got underway with 53 wheelchair competitors leaving Hopkinton.

[11] Hiroyuki Yamamoto of Japan aimed to make a move at the 5-kilometre (3.1 mi) mark, and at 8 miles (13 km) into the race had built up a lead of 200 yards (180 m), which he held until the end to win in a time of 1:25:32.

[13] She was eventually caught when Ana Dulce Félix increased the pace and broke away from the main pack to gain a lead of 76 seconds.

Jeptoo managed to break away from the others after 40 kilometres (25 mi) when climbing an overpass to cross the Massachusetts Turnpike, and finished in a time of 2:26:25.

[14] In the men's race, Jason Hartmann and Fernando Cabada led during the early miles before a group of nine caught up before half-way.

[15][13] The pack of eleven passed half-way in a slow time of 1:04:44, before Robin Watson, Geneti, Micah Kogo, and Dickson Chumba made surges.

[13] However, it was Chumba's surge that broke up the pack; only Desisa, Matebo Omari, Geneti, and 2009 winner Deriba Merga remained, with Gebremariam, Kogo, Raji Assefa, and Korir falling a few seconds behind.

[17] Over 5,000 participants who were unable to finish due to the race being halted were given medals and priority to run in the 2014 Boston Marathon.