Red Sox legend David Ortiz will serve as the grand marshal of the 127th Boston Marathon on Monday. Here's what you need to know about the top athletes, where to watch, and what's new this year.
A mouthwatering match-up in New York with recent world XC champ Jacob Kiplimo taking on former World XC Champ and the World 10,000m Champ Joshua Cheptegei. Hellen Obiri and Molly Huddle headline the women's field.