12th anniversary of 9/11 (41 images)

Former Mayor Rudy Giuliani, left, and NYC Mayor Michael Bloomberg at the 9/11 Memorial during ceremony marking the 12th Anniversary of the attacks on the World Trade Center in New York,Wednesday, Sept. 11, 2013. New York City Fire Commissioner Sal Cassano is behind in the middle. UPI/David Handschuh/POOL..

Ester DiNardo, mother of Marisa DiNardo, clutches her image while attending the 9/11 Memorial ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York on September 11, 2013. UPI/Adrees Latif/POOL

Former Mayor Rudy Giuliani, left, and NYC Mayor Michael Bloomberg at the 9/11 Memorial during ceremony marking the 12th Anniversary of the attacks on the World Trade Center in New York,Wednesday, Sept. 11, 2013. UPI/David Handschuh/POOL..

A man reflects on the benches of the Pentagon Memorial at the Pentagon in Washington, DC on September 11, 2013. President Barack Obama will commemorate the 12th anniversary of the 9/11 terrorist attacks that killed nearly 3,000 people in New York, Washington and Shanksville, Pennsylvania. There are 184 benches in the Pentagon Memorial representing the 184 people who died at the Pentagon on September 11, 2001. UPI/Pat Benic