9-11 7th Anniversary Commemoration Ceremony at the World Trade Center site in New York

Democratic presidential candidate Senator Barack Obama (D-IL) (L) and Republican presidential candidate Senator John McCain (R-AZ) greet each other as they visit the site of the former twin towers, on the seventh anniversary of the attack on the World Trade Center, in New York September 11, 2008. (UPI Photo/Shannon Stapleton/POOL)