In the deadliest terrorist attack on American soil, 19 al-Qaeda militants hijacked four airplanes on the morning of Sept. 11, 2001. Two crashed into the twin towers of the World Trade Center in New York City, killing 2,750 people and demolishing the buildings. A third plane crashed into the Pentagon in Washington D.C., leaving 184 dead, while another plummeted into a field in Shanksville, Penn., killing 40.
TIME put out a special issue that included hair-raising reporting from lower Manhattan, where blood coated the sidewalk, and eyewitnesses who worked in the World Trade Center who described how the bodies, burnt to a crisp, fell from the sky.
“As the day unfolded, it looked awfully easy to declare war on us,” TIME wrote. “The attack was the perfect mockery of the President’s faith in missile defense: What if the missile is an American Airlines plane, and the pilot wants to kill you?”