Former first lady Laura Bush, from left, former President George W. Bush, first lady Michelle Obama and President Barack Obama hold hands to their hearts during the national anthem as friends and relatives of the victims of 9/11 gather for a ceremony marking the 10th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site, Sunday, Sept. 11, 2011, in New York. (AP Photo/Jason DeCrow)
Memorable moments: Ground Zero memorial ceremony
•1 January 1970
A collection of moments from the 9/11 anniversary memorial ceremony in New York.