In World War II, the Marines played a central role in the Pacific War, and the war saw the expansion of the Corps from two brigades to two corps with six divisions and five air wings with 132 squadrons. The battles of Guadalcanal, Tarawa, Saipan, Iwo Jima, and Okinawa saw fierce fighting between U.S. Marines and the Imperial Japanese Army. The secrecy afforded their communications by the now-famous Navajo code talkers program is widely seen as having contributed significantly to their success.
During the battle of Iwo Jima, Raising of the Flag on Iwo Jima, a famous photograph of five Marines and one Navy corpsman raising the American flag on Mt. Suribachi, was taken. Secretary of the Navy James Forrestal, who had come ashore earlier that day to observe the progress of the troops, said of the flag raising on Iwo Jima, "...the raising of that flag on Suribachi means a Marine Corps for the next five hundred years." The acts of the Marines during the war added to their already significant popular reputation, and the USMC War Memorial in Arlington, VA was dedicated in 1954.
By the wars end, the Corps had grown to include six divisions, five air wings and supporting troops totaling about 485,000 Marines. Nearly 87,000 Marines were killed or wounded during WWII and 82 earned the Medal of Honor With service in every war in US history including on-going operations in Iraq and Afghanistan, the Marine Corps has evolved into a 21st Century force with a unique, multi-purpose role in the modern United States military.
The Marine Corps is the second smallest of the five branches (Navy, Marine Corps, Army, Air Force, Coast Guard) of the U.S. military, with 180,000 active and 40,000 reserve Marines as of 2005. Only the United States Coast Guard, part of the Department of Homeland Security, is smaller. In absolute terms, the US Marine Corps is nonetheless larger than the armed forces of many major nations; for example, it is larger than the British Army.