In pictures: Commemorating the eleventh anniversary of 9/11
One World Trade Center, centre, rises above the National September 11 Memorial and Museum at the World Trade Center, Thursday, Sept. 6, 2012 in New York. Tuesday will mark the eleventh anniversary of the terrorist attacks of Sept. 11, 2001. The World Financial Center is on the left, and Four World Trade Center is at right.Mark Lennihan/The Associated Press
Members of the September 11th Education Trust meet in a restaurant overlooking the National September 11 Memorial and Museum at the World Trade Center, Thursday, Sept. 6, 2012 in New York. The trust is a non-profit organization dedicated to teaching the lessons of 9/11.Mark Lennihan/The Associated Press
Visitors to the National September 11 Memorial and Museum look at one of two reflecting pools at the World Trade Center, Thursday, Sept. 6, 2012 in New York. Tuesday will mark the eleventh anniversary of the terrorist attacks of Sept. 11, 2001.Mark Lennihan/The Associated Press
Stella Towers, 10, of Sydney, Australia leans into the South Pool during her visit to the 9/11 Memorial, ahead of the 11-year anniversary of the Sept. 11, 2001 attacks on the World Trade Center at "ground zero" in New York on Sept. 10, 2012.ADREES LATIF/Reuters
Visitors lay roses over the names of the first responders at the South Pool of the 9/11 Memorial, ahead of the 11-year anniversary of the Sept. 11, 2001 attacks on the World Trade Center at "ground zero" in New York on Sept. 10, 2012.ADREES LATIF/Reuters
Visitors to the National September 11 Memorial walk below the rising towers 1 World Trade Center, left, and 4 World Trade Center, Monday, Sept. 10, 2012 in New York. Tuesday will mark the eleventh anniversary of the attacks of Sept. 11, 2001.Mark Lennihan/The Associated Press
Roses and a U.S. flag are laid amid the names of the first responders along the South Pool of the 9/11 Memorial, ahead of the 11-year anniversary of the Sept. 11, 2001 attacks on the World Trade Center at "ground zero" in New York on Sept. 10, 2012.ADREES LATIF/Reuters