Joe Fennel witnessed both explosions, and the chaos that followed, he says he tries not to think about the bombing, but one year later he can't help but reflect on the effects of the attack.
"It was just a typical Boston day," he says. "The weather was wonderful, crowds were great."
The mood took a sharp turn, moments after Fennel crossed the finish line.
"I heard the explosion and turned around and saw the same thing that everybody's seen a million times, a big puff of gray smoke," he says. "It was a big enough explosion that you knew whatever it was it wasn't going to be good."
At first Fennel thought it was a terrible accident, and then another blast rocked the street.
"You start kinda putting it together and you go, 'Wow! Alright, that's what's going on,'" he says. "'I wonder how many more of those are going to go off.'"
Fennel made his way through the chaos to meet his family, and says by the time he found his cousins, he was angry.
"I'm going through there and I'm seeing all these young kids and stuff, and so I was trying to stay positive," Fennel says. "I could only imagine the innocent people that got hurt, and I was just mad that someone would attack something like the fabric of the Boston Marathon because it means a lot to me."
Fennel has close ties to the city, and the race.
"My mom as a little girl was out watching the marathon, and all my cousins still go," he says. "It's just a magical deal, and no race that you go to anywhere in the world gets the fan support in Boston. You have people cheering for you for 26 miles."
He's sure the support this year will be stronger than ever.
"There'll be some pain," he says. "Rightfully so, but I think the energy that is going to come from that event this year is gonna be amazing."
Fennel planned to be in the crowd to show his support and feel that energy, but says he couldn't make it this year.