President Barack Obama and his wife, Michelle, placed a wreath at the Flight 93 National Memorial today, arriving at the site to pay respects to the 40 passengers and crew who died a decade ago. The Obamas visited the Wall of Names. Each of the 40 marble slabs is inscribed with the name of someone killed in the crash of United Flight 93 on Sept. 11, 2001.
Some 3,000 people were gathered at the Flight 93 memorial as Obama walked to a security barricade to shake hands. Others took his photo and sections of the crowd chanted "USA! USA!" One man called out: "Thanks for getting bin Laden!"Later, the president planned to visit a memorial outside the rebuilt Pentagon. Click through the gallery for scenes from the day around the world.