THE BORDER In December 1999, Algerian Ahmed Ressam was stopped trying to cross from Canada to the U.S. in an explosives-packed car, which he intended to use in a plot to blow up LAX
MINNESOTA Zacarias Moussaoui was detained in August 2001 after arousing suspicion at a flight school. A local FBI agent says an HQ "roadblock" thwarted a pre-Sept. 11 investigation
OKLAHOMA In 1993, years before suspected "20th hijacker" Zacarias Moussaoui flunked out of flight school in Norman, alleged al-Qaeda affiliate Ihab Mohamed Ali got his pilot's license here
SAN DIEGO Hijackers Nawaq Alhamzi and Khalid al-Midhar lived in California...