September 11th memories fade as generations change

As America marks the 15th anniversary of the 9/11 attacks, there are fewer of us who remember the horrific events of that day firsthand. By some estimates, nearly one out of five people in the U-S have birthdays after the attacks of September 11, 2001. So how do we make sure Americans remember 9/11? Purdue University History Professor Caroline Janney may have some answers and advice and she talked with WGN’s Steve Grzanich.