reporter: the day the bombs went off at the boston marathon, veteran boston globe photographer john tlumacki 200 photos. >> i have trouble going back to the finish line of the marathon because i can visualize where everybody was when i photographed them. >> reporter: he was especially haunted by the images he took of 17-year-old sidney corcoran and her 48 mother celeste. shrapnel shattered sidney's arteries. >> by photographing them, i felt like i took advantage of them even though i was doing my job, that i was guilty of maybe depriving them of their dignity. >> reporter: tlumacki felt compelled to meet them. two weeks later when he finally did, he apologized. >> i didn't want to have that image in my head of them lying on the ground. i needed a new picture of them, and i asked them if i could take a picture of them, and they just kind of looked at each other and smiled. >> they grew closer as he documented their recovery. >> what are some of the moments that stood out to you? >> one of first times celeste stood up without holding onto anything. that was day one of celeste being energized,

some terrific folks, first responders who did heroic work at the scene of the attacks as well as john tlumackiotographer who captured one of the most famous images of the day. thank you all for being here, thank you for your work, for your service that day and on all the days you provide your service, and we're going to talk about understanding one year later. before we do that though, i want to bring in our harry smith whos had this report on how boston is still trying to come to terms with the events of a year ago. >> reporter: you can tell a lot by the looks on people's faces. the wounds are not healed, not yet. at the boston public library, there's an exhibit of mementos from the miakeshift memorials that appeared after the marathon bombing last year. >> it's sad. of it brings back a lot of memories, a lot of, you know, fear, anxiety. >> the mood is respectful, even sacred. >> it takes a little while to absorb it, and i think you want to stand here with respect. >> reporter: up boston street at the forum restaurant, site of the second explosion, manager chris loper says the memories are st

reporter: the day the bombs went off at the boston marathon, veteran "boston globe" photographer john tlumacki>> i have trouble going back to the finish line of the marathon because i can visualize where everybody was when i photographed them. >> reporter: he was especially haunted by the images he took of 17-year-old sydney corcoran and and her 48-year-old mother, celeste. sharp nel severed sydney's femoral artery. >> by photographing people the way i did, by photographing sydney on the ground helpless, and celeste, i felt like i took advantage of them, even though i was doing my job, that i was guilty of maybe depriving them of their dignity. >> tlumacki felt compelled to meet them. two weeks later, when he finally did, he apologized. >> i didn't want to have that image in my head of them laying on the ground. i needed a new picture of them and i asked them if i could take a picture of them, and they just kind of looked at each other and smiled. >> reporter: they grew closer as he documented their recovery. what are some of the moments that stand out for you? >> one of the first times that c

. >> john tlumacki, again, reflecting on your image that you took, that's the kind of image that stands the test of time, marking a moment in history. what's it going to represent to you and do you think to people who see it in years to come. >> i think it's going to be the reminder of what happened in that terrible marathon. hopefully this year i'll be able to replace that image with something more joyful. survivors crossing the finish line with their family. i'm going to be there, i'm going to be standing on the finish line doing my job, and i want to replace that image. i don't want people to keep coming back and thinking that's the way it was. i want people to come and look -- go online, look at the "boston globe" and say what a beautiful picture. >> well said. we're going to leave it there. thank you very much. thank all of you for being here and thank you all on the panel as well. >> thank you. >> boston strong for sure. we're coming back here. i'll be joined by our special guest, documentary maker ken burns has come around to discuss how one of the most powerful speeches in ameri