CHICAGO The Chicago Marathon has kicked off, featuring runners from more than 120 countries and all 50 states
Chicago Police have stepped up security for the Sunday morning event in the wake of the Boston Marathon bombings.
Most runners and spectators say the weather is at the forefront of their minds. Temperatures were in the mid 40s at the 7:30 a.m. race start.
Before the race, organizers held 30-second moment of silence for the victims of the bombings and their families.
The hottest race day was in 2007 when the temperature reached 89 degrees. The coldest was in 1988 when it was a chilly 21 degrees.
This year's marathon is expected to draw 45,000 runners and more than a million spectators. It goes through 29 of the city's neighborhoods.