A retired fire chief from Shanksville, Pa. said his life changed dramatically on September 11, 2001.
Terry Shaffer was among the first responders on scene when one of the four hijacked planes came down in a field in western Pennsylvania.
Shaffer talked about the day with students at Twin Valley Middle School in Caernarvon Township.
"It's obviously the most traumatic day of my life. You can't believe this happened," said Shaffer.
Shaffer said he's spent the past 11 years making sure no one forgets the events of that day.