Published May 16. 2021 12:01AM By Lisa McGinley Everyone old enough to watch television on Sept. 11, 2001 knows where they were when the planes hit the north and south towers and the Pentagon. The terrorist attacks using four commercial aircraft as weapons changed history in a way that seems unforgettable to those who lived through it. For some it has already faded; that is proving to be a danger. The people bringing this lapse of memory to attention are members of the group Friends of Flight 93, who support the Flight 93 National Memorial in Stoystown, Penn. When they volunteer on the site where United Flight 93 crashed into a field, they find visitors are often surprised to hear about what happened there. The guides tell them the story of passengers and crew who knew, from mobile phone calls with friends and family on the ground, that three other planes had hit major targets. Rather than let their flight slam into the U.S. Capitol or the White House, they fought for control of the plane. All aboard died when it crashed.