"There was no mistaking what that was. It was horrible. So loud, and you felt it," said Maria Schreiber.
A little more than three minutes after Maria Schreiber crossed the Boston finish line last year, the first of the two bombs went off. Maria was maybe 50 yards away. Chaos, shock, fear followed. But at the same time, people rushed to help with comfort and reassurance from strangers.
That meant a great deal to Maria, a three-time Boston finisher who's going back to run it again to thank Boston and honor the survivors.
"There are people who really struggled and they are coming back and learning to dance again and walk again, and getting back to their lives. I'm so inspired," said Schreiber.
"We're just there to support the runners. Supporting everyone there supporting us," said Katie Marquard.
Katie Marquard and Stephanie Yee were a mile from the finish last year when the blasts occurred. They're going back to finish the unfinished, and to also say thanks.
"We were rescued so well by complete strangers. We want to go back and celebrate and thank Boston for taking us in," said Stephanie Yee.
Molly Akers will be running too as part of Team MR8 - a group running in honor of the youngest bombing victim - 8-year-old Martin Richard who died instantly in the blast.
"The picture of him holding the sign - no more hurting people, peace - and my friends said we have to do something for him," said Akers.
This past weekend they set up a fun run to raise funds for the Richard Foundation, a family that's inspired strength in others after such unspeakable loss.
"Our thoughts are going to be with the Richard family, and all the other bombing victims and people suffering and the courage and bravery it took for them to get back there a year later and do it again," said Akers.
Akers and the rest of Team MR8 have never met the Richard family before, but they will this weekend just before the marathon.