An animal skull rests on a lamp post base along the U.S. and Mexico border in Naco, Arizona September 7, 2011. Since the attacks on 9/11 ten years ago, the U.S Border Patrol and National Guard Troops have increased security along the border in Arizona. The September 11 attacks, orchestrated by al Qaeda militants, led to the largest shakeup of the U.S. federal government since the Cold War, with the founding of the Department of Homeland Security in 2003. As part of its core mission of preventing "terrorists and terrorist weapons from entering the United States," the new Customs and Border Protection agency has since sharply boosted security on the nation's borders. Picture taken September 7. REUTERS/Joshua Lott (UNITED STATES - Tags: CRIME LAW SOCIETY IMMIGRATION)