[explosion] jim bacon: we heard a tremendous blast, and all of a sudden all chaos ensued. everybody started running. rick schwein: he set the thing up to hurt people in a mass way. [crowd clamoring, whistle] mark mckay: we don't know if that person is going to strike again. [blows whistle] let's go! mark mckay: who did this? is it part of a strategy or is it a singular event? we didn't know any of that. [theme music] hello, and welcome to how it really happened. i'm jesse l. martin. in the summer of 1996, all eyes were on atlanta, georgia for the centennial olympics. the southern city put on quite a show for the opening ceremony as muhammad ali lit the olympic flame. but just eight days later, at a celebration in centennial park, a security guard noticed a suspicious backpack under a bench. security and law enforcement moved quickly to evacuate the massive crowd, but time was not on their side. this is how it really happened. [indistinct chatter] it's a weekend night in atlanta. it's hot. the streets are packed. [groovy music] there is entertainment at centennial park. the

jim bacon: right now, we've got thousands and thousands of people evacuating the area. the police moved in very quickly. and as far as we know now, from eyewitness accounts, we've got some injuries. i remember very distinctly the smell of gunpowder. i don't think i'll ever forget that. . you having a good time? [cheering] oh, yeah. [explosion] whoa. jim bacon: right now, it is just an absolutely chaotic scene, and millions of people here are running up the street, and the police are running in. i can't personally see anybody that's hurt, but several eyewitnesses have told me varying accounts of injuries. and the accounts that i have heard make it sound like the injuries are indeed serious. [ominous music] i looked around, people were screaming, many injured, laying around. jim bacon: a policeman was hit with shrapnel and was bleeding profusely on the ground. a number of other people in the area here have been hit and are hurt. tom davis: we just tried to deal with that situation the best we could. going person to person trying to determine the severity of their injuries