Once Andrew Phillip's school principal had had time to digest the events that had just unfolded, the decision was made to proceed with class at Lakeland High School as normal. The kids would remain at school, and information would be parceled out as it became available.
The then-16-year-old can still hear the silence that overtook the normally loud and bustling hallways that day in Westchester, NY. The vast majority of students were walking around lifeless, like zombies, he said.
Others tried to use their cell phones to call their families, but there were no words uttered from their mouths. No one could get through anyway because phone lines were over capacity.
Name: Andrew Philip
Hometown: Westchester County, NY
Age on 9/11: 16
Education: PhD candidate, Auburn University
In his own words:
"I don't think I ever heard of al-Qaeda before the attacks. Like most teens at the time, I was blissfully unaware of a large number of things outside my small world. I had seen the towers before, as I grew up in the city before moving to the suburbs when I was about to start high school. But I didn't have a real understanding about them, and had never been inside. Mostly, I remembered them as a major part of the skyline."
Some teachers did their best to act normally and go about with the day's lectures. Others tried to talk to their students about how they were feeling. Others simply let the teenagers sit in more silence.
One image of that larger-than-life school day sticks out a decade later. As Philip watched as a second plane fly into the World Trade Center, a close friend at his side began to sob uncontrollably about her father, who worked nearby.
"At that age, you aren't very equipped to help people deal with grief," he said. "From that moment in class when my friend was crying and wondering if her father was alive to the later times when I heard of other people who had lost loved ones, I had to quickly learn methods for comforting others, including myself."
The previously sheltered 16-year-old was shaken. Philip said he had recurring nightmares for a year or two. Visions of nuclear bombings, planes crashing into buildings and other types of mass attacks filled his head as he lay in bed.
Worries over another attack didn't just cause Philip to lose sleep. They also compelled him to remain as vigilant as possible. Beginning on 9/11 and for weeks to come, the teenager went home every day and watched CNN, sometimes until he fell asleep at night.
"For many years whenever there was a major event, like the ball drop or the tree lighting, I felt like I was just waiting for it to happen," he said. "Some of the worst times were during fireworks for the Fourth of July. Just the sound was disturbing."
And it's in those intense emotions that Philip finds the legacy of 9/11 - a shocking realization that we, as a nation, are not as invisible as we had been lulled into thinking. Like most teens at the time, he was blissfully unaware of the world outside of his own.
"But still, for those of us that grew up during the attacks, I think there will always be that lingering sense in the back of our minds that it could happen again, that something worse could happen," he said. "I think it brought us closer to reality."
Now 26, Philip is a candidate for a PhD in psychology at Auburn University, and is very interested in how 9/11 can be used as a teaching tool in his field.
"Events like this and Katrina have given us good road maps for how to go about handling the psychological trauma following disasters in modern times, where media coverage and instant communication makes what used to be fairly isolated events a shared experience in many ways," he said.