Sitting in a conference room on the 105th floor of the World Trade Center's South Tower, all Joe Dittmar and his colleagues noticed when a plane hit the North Tower was a flicker of the light.
An announcement came over the PA system: the incident in the North Tower was contained. South Tower occupants would be safe where they were, but could evacuate if they wanted.
Dittmar was the last person to leave the room. He chose evacuation, taking the fire stairwell instead of the elevator. He was in the fire stairwell when the call for evacuation came.
When the plane hit the South Tower, he was fewer than ten floors below the impact.
“That fire stairwell that we were inside just started to shake back and forth in ways it shouldn’t shake back and forth," Dittmar said. "You see the concrete start sputtering out, the handrails are breaking away from the wall. The steps were like waves in the ocean, fluctuating underneath our feet, and we felt a huge heat ball blow by us. We smelled jet fuel and rocked for what felt like forever. It was probably seconds or a minute, but it just felt like forever.”