UCLA professor Luwei Ying marks the milestone with a frank discussion about how the attacks reshaped the world and why resisting fear and division remains one of its most important lessons.
James Gelvin suggests volunteers are drawn to a value system that asserts aggressive machismo, disparages work, and sustains the impulse for immediate gratification.
Jeffrey Simon writes that the threat can never be completely eliminated but that there are ways law enforcement authorities can use technology to help mitigate it.