"That was fantastic," Christy Pegg, 38, of Malvern, said after high-fiving a receiving line of Army Reserve and National Guard soldiers at the finish.
"Without doubt, there was a different vibe this year," she said. "Not so much competitive but collaborative."
Mayor Nutter, out cheering runners at Broad and Walnut Streets, said, "I think there's a tremendous sense of emotion. There's a resilience and a resolve. This running community is great here in Philadelphia. They are committed not just to the race but to making sure we demonstrate that no matter what anybody does, no matter what they try to do, we are Americans. We are strong."
Ayele Feisha won the race in 47 minutes, 3 seconds - 8 seconds better than the next-fastest runner. The fastest female runner was Askale Merachi, who finished in 53:46. Feisha and Merachi are natives of Ethiopia. The fastest American-born runner was Cole Atkins, who finished in 47:44.
Among the 38,000 who registered were two old friends from Sterling High School in South Jersey - Kirk Cooper and Mike Egan, both 35, who ran with American flags. "I ran for those who couldn't," Cooper said.
"Around City Hall, you made eye contact with a stranger for a second or two and it meant something," Egan said.
Three sisters, Katie, May, and Sarah Limbach, ran in red custom-made "Brotherly Love Boston" T-shirts, with the B's resembling the logo of the Boston Red Sox and the Love a replica of the sculpture in LOVE Park. Sarah Limbach, of Philadelphia, ran the Boston Marathon.
"It gave me so much power and energy," May Limbach, who lives in New York, said of the shirt. "People were going nuts about it. This is the first race I've run without music, and I didn't need it."
John Graham Jr., 29, of Connecticut, a fourth-year medical student at Temple University who ran in a Boston shirt, said he "got caught up in the emotion." He went out way too fast, and paid dearly the last four miles.
Lori Lynch, 42, of Lafayette Hill, said the weeks leading to the race, sponsored by Independence Blue Cross, were "a little scary," but once she reached the starting line - "you looked around and it felt safe."
Before the start, Nutter invited runners to observe a moment of silence. So many have rarely been so quiet.
The race began to the Neil Diamond hit "Sweet Caroline" - an anthem at Boston Red Sox games - blasted from speakers as runners picked up speed.
Near the start, residents sat in folding chairs and perched on steps as they cheered.
"It's so beautiful to see so many people running, despite Boston," said Sharon Lewis, who watches the race every year with her sister Dianne Canery. "You can't dampen the spirit of real Americans."
Spectators said the visible police presence made them feel safe.
Stationed outside the Hyatt at the Bellevue hotel at Walnut Street - not far from where former Gov. Ed Rendell, sporting a Red Sox T-shirt, slapped hands with runners - Terry Devaney of Bushkill said she had seen police looking in trash cans before the race.
"We feel really good about it," said Devaney, whose 60-year-old husband, Jim, and 29-year-old daughter, Abby, were running. It was her husband's first time, inspired by watching his daughter last year.
The sea of Boston clothing and signs "definitely made the race more emotional," said Stefanie Bucholski, 25, of Collingswood, who ran with her sister Abbe Elliott, 33. Running for the first time, Elliott said crowds cheered for her so much, "there were about three different times I wanted to cry."
There were many moments of triumph.
Andrew Kessler, 18, who suffers from autism and was profiled recently in The Inquirer, was beaming before the race began, and was even happier when he finished 91 minutes later.
"He had the time of his life," said his father, Chris.
Joe Kain ran with a shirt that said, "Pam McDonald Will You Marry Me?" He carried the ring and got down on one knee near Pattison Avenue, where she was watching. She said, 'Yes' and fueled him to the finish with a kiss.
"I don't think I'll ever run that fast again in my life," said Kain, of Philadelphia. "Probably because I had such a good reason to get to the end.
"We walked together to the end," he added. "It was great because everyone was wishing us congratulations as we walked. I love her so much. It was the perfect day."
It wasn't a perfect day but certainly an unforgettable one for Heather Garay-Yoder, 25, from outside Reading, who finished wearing her husband's dog tags and wedding ring. The subject of a story in Sunday's Inquirer, she started running in August when her husband, Chief Warrant Officer Jarett Yoder, deployed to Afghanistan.
He coached her from afar, but died April 9 when his Apache helicopter crashed. Heather hadn't run a step since he died. A pilot, Yoder, 26, was a member of the Pennsylvania Army National Guard.
"It was rough, but I did it," a smiling Garay-Yoder said at the finish. "Jarett helped me through. I'll do it again next year. I'm happy."
Contact Michael Vitez at 215-854-5639, firstname.lastname@example.org, or follow on Twitter @michaelvitez.
Inquirer staff writers Aubrey Whelan, Maddie Hanna, Zach Berman, and Sulaiman Abdur-Rahman contributed to this article.