mostfrighteninghistory on Instagram: "On September 11, 2001, the world watched in shock as a series of coordinated terrorist attacks shook the United States. Four commercial airplanes were hijacked by terrorists, with two planes flown into the Twin Towers of the World Trade Center in New York City, causing both buildings to collapse within hours. A third plane hit the Pentagon in Arlington, Virginia, while the fourth, United Airlines Flight 93, crashed into a field in Pennsylvania after passenge