The faces of the London bombers are familiar to the world because they were captured by thousands of video cameras in the London Underground. The British are the most photographed people on earth, but does it make them safer? A look at the role of surveillance cameras in fighting terrorism.
Martin Gill, professor of criminology at the University of Leicester's Scarman Center; director of Perpetuity Research and Consultancy International (PRCI)
Monique Bond, spokesperson for the Chicago Office of Emergency Management and Communications
Greg Hull, director of operations safety and security with the American Public Transportation Association
Brian Jenkins, senior adviser to the president of the Rand Corporation; director of the National Transportation Security Center at the Minetta Transportation Institude in San Jose, Calif.