The 120th Boston Marathon takes over the streets of greater Boston on Monday, and the runner to beat in the men's race is two-time champion and 2015 winner Lelisa Desisa. Desisa, from Ethiopia, has won two of the last three Boston Marathons. Caroline Rotich of Kenya is back to defend her 2015 title. She is regarded as more of a contender than a favorite to win and repeat. About 30,000 runners will take to the 26.2 mile course that ends with a straightaway down Boylston Street in downtown Boston.