The September 11 attacks in 2001 were the deadliest terrorist acts in human history, killing 2,996 people—including 19 hijackers—with the Twin Towers in New York City bearing the brunt of the casualties, while 125 died at the Pentagon and 265 aboard four hijacked flights. The 2,977 victims were overwhelmingly civilians, but they also included 344 NYC firefighters, 71 law enforcement officers, 55 military personnel at the Pentagon, and citizens from at least 102 countries. Long-term health effects have proven devastating: by 2014, over 1,400 rescue workers had died from related illnesses, and by 2013, more than 1,140 people had been diagnosed with cancer from toxic dust exposure at Ground Zero. The official death toll was later revised upward as medical examiners added victims who succumbed to dust-related diseases, raising the World Trade Center count to 2,606 and the overall total to 2,996. Evacuation efforts were shaped by lessons from the 1993 World Trade Center bombing, leading to improved radio repeaters, emergency lighting, and drills—yet the 110-story towers still lacked designs for complete evacuation, as most U.S. high-rises at the time were not built for total crisis departures.