There were many fine photographs that captured the horror of 9/11, from images of the attack itself captured by James Nachtwey to a chronicle of the wounded city by Joel Meyerowitz. But perhaps no single photograph encapsulates the collective reaction to the attack quite as thoroughly as the one Time photo editor Patrick Witty took in Lower Manhattan that morning. Now, twelve years later, Witty is on a quest to find out the names of his subjects that morning. As he wrote in a LightBox post titled "Help Identify This Photo: The Moment The Towers Fell" this morning:

I took this photograph exactly 12 years ago today, just as the South Tower of the World Trade Center started to collapse: a cross-section of New Yorkers, united in terror, standing at Park Row and Beekman Street in lower Manhattan. Since then it’s been published dozens of times in newspapers and magazines across the world, but I’ve never known the names behind the faces. Last year I posted the photo on Facebook and Twitter in hopes of discovering their identities. After it was shared more than 10,000 times, I now know two of them.
 

Twitter certainly responded to Witty's post of the photograph:

In an email to The Atlantic Wire, Witty says, "The second I took this picture there was a loud crack behind me and the South Tower began to collapse. Everyone, including myself, started running. And seconds later the entire area was blanketed in white dust. So obviously, I didn't get a chance to ask anyone their names. But I've always wanted to know what happened to everyone, and I still do. It's so easy to share photos on social media that it seemed a natural solution in trying to discover their identities."

He adds that, despite the attention his post has gotten, "I haven't had any leads yet today." That will hopefully change.