How the September 11, 2001 attacks unfolded

Americans are marking the 11th anniversary of the September 11 attacks with relatively low-key ceremonies. The main event will be the ritual reading at New York's Ground Zero of the names of the 2,983 people killed both on 9/11 and in the precursor to those attacks, the 1993 car bombing of the World Trade Center. A look back over the events of the fateful day in 2001.