Former Secretary of Defense Donald Rumsfeld and current Secretary of Defense Leon Panetta joined them as a wreath was set at the point of impact at the Pentagon.
President Barack Obama and Michelle Obama visited Arlington national cemetery and the area where the dead from Afghanistan and Iraq are buried. They hugged and talked with grief-stricken families.
Obama invoked the common purpose that arose from carnage a decade ago in telling Americans that the nation cannot be broken by terrorism "no matter what comes our way."
Behind them was the Pentagon memorial where 125 benches face the Pentagon where the victims died. Fifty-nine face out toward the sky on the flight path of American Airlines Flight 77. They represent the victims on the plane.
The Associated Press contributed to this report.
