On Patriot Day, September 11, the US Flag is flown at half-mast at the White House and all US Government buildings and establishments throughout the world; Americans are also encouraged to display flags in and outside their homes. In many organizations, a moment of silence is observed to correspond with the attacks, beginning at 8:46 a.m. Eastern time, when the first plane struck the North Tower of the World Trade Center on September 11, 2001.