EE.UU. conmemora el 10º aniversario del 11-S
ARLINGTON, VA - SEPTEMBER 11: Members of the Patriot Guard Riders and other volunteers raise a large American flag from the ladder of a fire truck in a parking lot overlooking the Air Force Memorial and the Pentagon on September 11, 2011 in Arlington, VA. The group raised the same flag earlier in the day in Shanksville, Pennsylvania, and will raise it later in New York City. Brendan Hoffman/Getty Images/AFP
U.S. President Barack Obama and first lady Michelle Obama meet families of 9/11 victims at the Pentagon Memorial on the 10th anniversary of the attack on the Pentagon in Washington September 11, 2011. REUTERS/Kevin Lamarque (UNITED STATES - Tags: DISASTER ANNIVERSARY)
U.S. President Barack Obama (L) and first lady, Michelle Obama (R) walk along the memorial site for the victims of Flight 93 during ceremonies marking the 10th anniversary of the 9/11 attack in Shanksville, Pennsylvania, September 11, 2011. REUTERS/Jason Cohn (UNITED STATES - Tags: ANNIVERSARY DISASTER)