President Obama & First Lady Michelle Observe a Moment of Silence on September 11, 2012

President Barack Obama will spend Tuesday marking the 11th anniversary of the Sept. 11 attacks. He and first lady Michelle Obama will gather with White House staff on the South Lawn to observe a moment of silence. That will take place about the time of the first attack, when American Airlines Flight 11 struck the north tower of the World Trade Center in New York City. The president is then scheduled to attend a memorial ceremony at the Pentagon. In the afternoon, Obama plans to visit Walter Reed medical center in nearby Bethesda, Md., where he'll spend time with wounded veterans and their families.