Today, more than 200,000 active-duty and reserve Marines are serving air, land, and sea. The Marines pictured here respond, "I do" during the oath of office at the US Naval Academy Class of 2012 graduation and commissioning ceremony.
Every recruit received at Parris Island is transformed by legendary Marine drill instructors like the one pictured here. Marine recruits are typically younger than those in the Corps' sister-service branches, and each DI wants to ensure they can survive combat.
Built in 1861, the Marine Corps Recruit Depot in Parris Island consists of 8,095 acres of various types of terrain for the recruits to use as their learning facility. About 20,000 recruits are trained here every year.
Marines also train to operate in the air. Here, a crew master observes an F/A-18C Hornet approach a refueling hose during Exercise Pitch Black 2016 at Royal Australian Air Force Base Tindal on August 9, 2016.
The Marine Corps also trains to fight and survive in water. Here, Marines conduct an underwater gear shed during a basic swim qualification course at Marine Corps Air Station Cherry Point, North Carolina, on March 16, 2016.
The "Darkhorse" Marines in the 3rd Battalion, 5th Regiment, suffered the highest casualty rate of any Marine unit deployed to Helmand province in southern Afghanistan, following the heavy Marine-led assault on Marjah. Here, some members of the unit are under enemy sniper fire in 2010.
Marine Lance Cpl. James Blake Miller, dubbed the "Marlboro Marine," became the face of the Iraq War after his photo was taken by a Los Angeles Times reporter in Fallujah in 2004.
One of fiercest Marine battles in Iraq was in Fallujah, known as the "city of mosques," in 2004. It was the only battle in Marine Corps history where leaflets were dropped to alert civilians that troops were coming and to unnerve the enemy.
In this iconic photo, a Marine looks on as a statue of Saddam Hussein is pulled down in central Baghdad's Firdaus Square on April 9, 2003.
Marines cover each other as they prepare to enter one of Saddam Hussein's palaces in Baghdad during Operation Iraqi Freedom in 2003.
In this photo from 1990, Marine David Gurfein sits next to a Christmas tree in Saudi Arabia during Operation Desert Storm.
In 1983, the US embassy in Beirut was bombed by Islamic terrorists. At the time, it was the deadliest attack on a US diplomatic mission. This photo shows a Marine wearing a gas mask while digging through the rubble to find survivors.
Khe Sanh, in southern Vietnam, faced the heaviest rocket and artillery attacks from the North Vietnamese. The Marine below was stationed there in 1968.
Marines scatter away from a CH-46 helicopter that is exploding after it was shot down during combat in Vietnam. At least 13 Marines were reported killed in the crash, with another three badly burned.
The Vietnam War was the next major US conflict. This Marine truck is passing under a welcome banner at the entrance to Da Nang in Vietnam in 1965.
Marines line up at a makeshift Post Exchange in Korea to get comfort items like candy, cigarettes, and soft drinks.
In the US, women began training at the Marine Corps Recruit Depot in Parris Island, South Carolina, in 1949. All female recruits are still trained at Parris Island.
The North Korean invasion of South Korea brought the US into the Korean War. This 1950 photo shows Marine air and ground units during the war.
Marines seen here atop an amphibian tractor celebrate the end of World War II and "Victory over Japan Day" in 1945.
Marines raise the American flag at the top of Mount Suribachi in 1945. This photo actually shows the second flag raised on the mountain that day. The first flag was too small to be seen easily.
Iwo Jima was a vital base for US forces to launch air raids on Japan, but it was fiercely defended by Japanese forces. Here, Marines battle at the foot of Mount Suribachi.
This photo shows a Navy corpsman giving a wounded Marine blood plasma on an island in the Pacific in 1944.
Marine artillerymen wearing barely any protective gear plug their ears while firing a 155 mm howitzer on northern Iwo Jima.
Marines from the Navajo tribe used their native language to send coded radio transmissions to units overseas. Navajo code talkers, like the ones below, seen in 1943, were said to be faster and more accurate than Morse Code. Intercepted Navajo codes were never successfully deciphered by the enemy.
Here, Marines on the South Pacific island of Bougainville slog through thick mud to get ammunition to the front line.
Here, Marines land on the Japanese-held island of Saipan in 1944. Amphibious warfare has been a mainstay of the Corps' operations.
In this 1943 photo, James Wrobel designs the insignia for Marine Fighter Squadron 312. The official Marine Corps emblem has an eagle, a globe, and an anchor. The eagle represents readiness and precision. The globe represents the Corps' worldwide presence. The anchor reflects the Corps' naval heritage and ability to access any coastline in the world.