It’s always difficult to determine precisely when an epochal event makes the transition from memory to history, but 2019 may well mark that moment for the terrorist attacks of Sept. 11, 2001.

This week’s 18th anniversary can be seen as both the legal coming-of-age of the cohort born in the wake of al Qaeda’s assault and the generational passing of the torch from the children of the Cold War to the children of the war on terror. This fall, college students born after 9/11 began arriving on campuses across the nation for the first time, and in recent months, the first candidates born after those attacks began applying to join the ranks of the New York City Fire Department, still haunted by the loss of 343 of its members on that day. Similarly, military recruits born after 9/11 are now being deployed to the wars that the attacks sparked, as well as to Guantanamo Bay, where they will guard al Qaeda prisoners captured before the young soldiers were born.

For 23-year-old Lachlan Francis, the attacks are among the earliest memories of his Vermont childhood. “My daycare provider picked me and other students up in her minivan and brought us back to her house,” he told me. She “frantically tried to call her daughter, who lived in Manhattan at the time,” while the children “sat transfixed in front of the couch, watching the video of planes crashing into the Twin Towers over and over and over again.”