As the U.S. campaigns against terrorism, new technologies will move to the front lines.
At 5:45 a.m. on September 11, Mohamed Atta and Abdulaziz Alomari passed their bags through an X-ray machine at the Portland International Jetport in Maine. A surveillance video camera recorded their faces for posterity. Atta, a man believed to have links to Osama bin Laden's terrorist network, walked calmly, wearing a blue dress shirt and dark pants. Alomari, in a white shirt and khakis, clutched a black bag, checking its contents. Three hours later, they and three other hijackers on American Airlines Flight 11 crashed a jetliner into the north tower of New York City's World Trade Center.