On September 11, 2001, the United States suffered the worst terrorist attack in its history. From the Pentagon and the World Trade Center to a field outside of Shanksville, Pennsylvania, the attacks claimed 3,400 lives. The events of that day also ushered in a new era in U.S. foreign policy—an era that would result in thousands more U.S. deaths for decades to come.
Less than a month after the September 11 attacks, the war on terror began when US and NATO allies launched military strikes in Afghanistan. Then, in 2003, the war on terror escalated further when the US launched an invasion of Iraq.