Ten years laterAP photo Ryan Lamke of Washington sits by the grave of his fellow U.S. Marine, Cpl. Benny G. Cockerham III, in Section 60 of Arlington National Cemetery Tuesday in Arlington, Va. Capt. Tyler Swisher, Navy Petty Officer 3rd Class Chris Thompson, and Marine Lance Cpl. Kenneth Butler also died with Cockerham when their Humvee was attacked by an improvised explosive device. Today marks the 10th anniversary of the U.S.-led invasion of Iraq.