In the United States, Patriot Day occurs on September 11 of each year, designated in memory of the nearly 3,000 killed in the September 11, 2001, attacks. Most Americans refer to the day as "Nine-Eleven (9/11)," "September Eleventh," or some variation thereof.
U.S. House of Representatives Joint Resolution 71 was approved by a vote of 407-0 on October 25, 2001. It requested that the President designate September 11 of each year as "Patriot Day." President George W. Bush signed the resolution into law on December 18, 2001 (as Public Law 107-89). It is a discretionary day of remembrance.
Initially, the day was called the Prayer and Remembrance for the Victims of the Terrorist Attacks on September 11, 2001. On September 4, 2002, President Bush used his authority created by the resolution and proclaimed September 11, 2002 as Patriot Day.
On this day, the President directs that the American flag be flown at half-staff at individual American homes, at the White House, and on all U.S. government buildings and establishments, home and abroad. The President also asks Americans to observe a moment of silence beginning at 8:46 A.M. (Eastern Daylight Time), the time of the first plane crash on September 11, 2001. (From: Wikipedia, license: CCA-SA)