Today marks the 11th anniversary of the Sept. 11 terrorist attacks. Clockwise from top left: President Obama and first lady Michelle Obama observe a moment of silence on the South Lawn of the White House; friends and relatives of the victims of attacks on the World Trade Center attend a ceremony at the National September 11 Memorial; the Tribute in Light illuminated in Manhattan; flag on names at the September 11 Memorial site.
Thousands are expected to gather today at the World Trade Center site in New York, the Pentagon, and Shanksville, Pennsylvania to read the names of the nearly 3,000 victims killed.
