Photographer Gives CNN Firsthand Account of Boston Bombing (Exclusive Video)

CNN's Anderson Cooper and Randi Kaye reveal the stories behind some of the most iconic images taken of the Boston Marathon bombing in a new special debuting Friday on CNN.

Anderson Cooper Special Report: Back to Boston -- Moments of Impact will look at the photographs that vividly captured "both the horror and the heroism of the event," according to CNN.

PHOTOS: Inside the Boston Bombing Manhunt

Cooper hosts with Kaye, who interviews many of the photographers who captured the images during the bombing and in the immediate aftermath and featured the first responders and even some of the law enforcement heroes during the manhunt.

In this clip, which is exclusive to The Hollywood Reporter, photographer Kelvin Ma gives a first-hand account of the explosion, which took place April 15 at the finish line of the marathon.

The special premieres at 10 p.m. ET/PT on Friday, with encores at 8 and 11 p.m. ET/PT on Saturday.

Kimberly Nordyke