While security was on the minds of many during their 26.2 mile journey through the city's streets, participants didn't let it stop them as the winning runner set a new course record in what has become a historic Chicago Marathon.
Dennis Kimetto of Kenya won the male division with an unofficial time of 2:03:45, breaking the previous record set last year of 2:04:38.
The winners of the wheelchair division finished the race in less than 2 hours. As a group of wheelchairs crossed the finish line a number of volunteers clapped and cheered.
Ernst Van Dyk of South Africa won the male wheelchair division with a time of 1:30:37 and the winner of the female wheelchair division, Tatyana McFadden of Champaign won with a time of 1:42:37.
At 11 a.m., fatigue and pain were on every face as they turned north onto Michigan Avenue from 35th Street in Bronzeville at the 23-mile marker.
One runner lie on the curb, struggling to get up. After some water he got to his feet and told Bob Arendt of Chicago that he'd finish the marathon walking.
Arendt, 52, was there cheering on his daughter-in-law.
"His legs cramped up and he kind of went down," Arendt said of the marathoner he helped. "We got him some water and encouraged him on."
Shortly before 11 a.m., Chicago Fire Department spokesman Larry Langford said Superior Ambulance Service has been handling any medical calls arising from the race. Chicago Fire Department personnel has been merely assisting them, so far.
Langford couldn't provide the number of calls Superior has responded to, but he said the Fire Department hasn't transported any runners to hospitals.
As the runners raced along State Street, police officers in bright yellow vests kept watch at every intersection, lending a sense of reassurance to many in the crowd for the 36th annual race.
"You always think about safety because you never expect (violence), but I haven't felt uncomfortable at all," said Belinda Musgrave, who had come from Houston, Texas to cheer on her friend, Rhonda Kersgieter. "They seem to have everything under control."
Among the people at the end were a number of uniformed Chicago police officers who were standing guard behind the fence along side the finish line area.
A few of the uniformed officers were wearing bulletproof vests that read, "Department of Homeland Security POLICE" and walked through the area. They were accompanied by a homeland security K9 officer who was walking a bomb-sniffing dog.
The dog, appearing to be shepherd, wore a patch on its shoulder that read, "DO NOT PET."
Chicago Police officers seemed to be posted at nearly every intersection downtown as the city heightened security measures.
It was the bombing during the Boston Marathon earlier this year that inspired Marcy Wrzesinski to stand outside her apartment building on Sunday to cheer on the runners as they passed mile four in the Old Town neighborhood.
"The Boston Marathon I think freaked people out," Wrzesinski said.
A 10-year resident of Chicago, Sunday was the first time Wrzesinski made it out to watch the race.
"I normally watch from my bedroom window," she said. "I didn't want to shy away from it this year. I wanted to come out and give my support. Go America."
Wrzesinski and her husband Chet said they had not noticed extra security measures this year, except that newspaper boxes in their neighborhood had disappeared.
Spectators who had gathered on Wells St. in Old Town said they were surprised that there were so few uniformed police offices around.
"It's good that you don't see the presence because that makes people uncomfortable," said Kelly Kane, 43, who was cheering runners on as they approached mile 11.
Some runners high-fived and shook hands with the few officers who were visible along the route, said Bill Deitrick, a Gold Coast resident.
"I told the officer, I said, 'This is the best of humanity,'" Deitrick said.