Cheering and even leaping into the crisp Chicago air as they crossed the start line Sunday, tens of thousands of runners showed no fear in the first major US marathon since the Boston bombing.
Security was certainly tight and a massive police presence reassured fans and family members that everything that could be had been done to protect the 26.2 mile course.
But the new restrictions and massive show of arms -- including federal marshals carrying machine guns among the crowd -- did little to take away from the jubilance of watching 45,000 people push themselves to the limit.
"I'm really emotional," said Lindsay Decker, 23, who was supporting her sister's first marathon. "I cried when I saw her -- I'm so proud."
Decker hadn't thought too much about the Boston attack until she saw a truck marked "explosives team" parked on the street and her brother-in-law pointed out snipers positioned on rooftops.
"I'm not worried," she told AFP. "I feel pretty safe because there's a lot of cops around."
The Boston attack killed three people and injured more than 200 others when two pressure cooker bombs went off near the marathon's finish line on April 16.
Canadian wheelchair racer Diane Roy, 42, was in Boston for the race but had long finished when a friend called with the terrible news.
The attack was on her mind at her next big race in London -- where she came in 9th -- but she refuses to let it intimidate her.
"I'm going to focus on my course," she told AFP two nights before race day.
People need to stand up to terrorists and show them that life will go on despite the threats, said Philippe DuBois, 43, who flew in from Paris for the race.
"The attack gave me even more motivation to go to the United States for a marathon," DuBois said. "I've thought about it, but for me I want to encourage and support marathons."
The enthusiasm of the crowd was contagious.
Some runners wore tutus; others donned capes and costumes. A few even juggled. Fans rang cow bells, banged noisemakers and waved signs of support. Upbeat music poured out of speakers along the course.
Cool temperatures made for perfect conditions as the massive field ran past sun drenched trees just starting to show their fall colors.
"The world will watch the endurance of the human spirit to persevere," Chicago Mayor Rahm Emmanuel told reporters.
"An entire city, an entire country and an entire world saying 'we will not be deterred.'"
Race officials held a brief moment of silence at the starting line in honor of the Boston victims and encouraged runners to wear special laces they received in exchange for a donation to the One Fund Boston.
"The heartbreaking events left a lasting impression on all of us," Chicago marathon race director Carey Pinkowski said at a recent press conference.
"It was evident to me and our entire organization how strong, how determined and how united the running community is. We move forward with confidence, we move forward with strength."
An estimated 1.7 million spectators were expected to line the course Sunday.