Taken from Wikipedia.com

Valiant Shield was a large war game conducted by the United States military in the Pacific Ocean in June 2006. The exercise began on 19 June 2006 and lasted for five days, concluding on 24 June 2006. According to the Navy, Valiant Shield focused on cooperation between military branches and on the detection, tracking, and engagement of units at sea, in the air, and on land in response to a wide range of missions. The exercise involved 22,000 personnel, 280 aircraft, and thirty ships, including the supercarriers USS Kitty Hawk, USS Abraham Lincoln, and USS Ronald Reagan. It was the largest military exercise to be conducted by the United States in Pacific waters since the Vietnam War, and it was also the first time observers from the People's Republic of China were allowed to view U.S. wargames. The exercise marked the first of what will become biennial exercises involving different branches of the U.S. military.