In the fall of 2016, while writer Elliot Ackerman was on assignment in Iraq for Esquire magazine, he found himself on a rooftop in recently liberated Fallujah, peering down at a knee-high cinderblock wall. Before he was a writer, Ackerman was a Marine infantry officer, and for a few tense minutes during the Second Battle of Fallujah, that wall had been all that stood between Ackerman and a barrage of enemy gunfire. Now, after all those years, it was still there. And as he looked out across the neighborhood where his platoon had fought a daylong battle in 2004, it dawned on him: Everything else he remembered from that day was there, too.