Patriot Day is observed annually on September 11th in the United States to commemorate the lives of those who died in the 2001 terrorist attacks on the World Trade Center in New York City and the Pentagon in Virginia, as well as those who perished when the hijacked United Airlines Flight 93 crashed in Pennsylvania. The day is marked by various observances, including a moment of silence at 8:46 AM Eastern Standard Time, which is the time the first plane struck the World Trade Center.