Chicago Marathon runners hit the streets Sunday morning, nearly six months after the Boston Marathon bombings, with more security lining race routes and spectator areas.

Runners from more than 120 countries and all 50 states observed a moment of silence for the victims and families before the race kicked off. Three people died and more than 260 were injured in the April 15 bombings.

Heightened security was evident with Homeland Security vehicles parked on a sidewalk on Michigan Avenue near the lakefront and bomb-sniffing police dogs walking the area. City snow removal trucks were repurposed to block closed A Chicago Police officer stands near the eight mile mark along roadways.