NATO heads of state and government walk on the "Two Banks Bridge" on the Rhine river in Kehl

France's President Nicolas Sarkozy and and U.S. President Barack Obama when they arrive with NATO heads of state and government on the "Two Banks Bridge" on the Rhine river in Kehl April 4, 2009. The North Atlantic Treaty Organisation (NATO) military alliance is celebrating its 60th anniversary this week at a summit co-hosted by Germany and France.