U.S. Marines use a 37mm gun to pounding Japanese pill boxes on May 9, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

Braving sniper fire, Marine Lt. Col. Richard P. Ross, Jr., places the American flag on a parapet of Shuri castle on Okinawa. This 1st Marine Division flag was the first to be raised over Cape Gloucester and Peleliu by that unit. The metal staff to which the flag is attached had been used for Japanese ensigns and bears the marks of American shell fire. (U.S. Marine Corps)

The main American landings occurred April 1, 1945 at the Hagushi beaches on western Okinawa. The battle would rage for the next 81 days. (U.S. National Archives)

The USS Tennessee bombards the Okinawa shoreline as Navy gunboats make their way to the island. The main U.S. landing took place on April 1, 1945 on the western side of the island. (U.S. Army)

Soldiers and Marines stormed the beaches with the help of amphibian crafts as heavy support fire from Navy battleships blanketed the beaches with smoke and dust at the beginning of the Battle of Okinawa. (U.S. Army)

At the beginning of the invasion of Okinawa, U.S. Army troops met little or no opposition. As infantrymen from 96th Division infantrymen engaged in their first hill and cave fighting, other 96th Division troops, in amphibian tanks turned south toward Sunabe. (U.S. Army)

Infantrymen from the 77th Division trudge toward the front lines past mud-clogged tanks and mud and heavy rains increased the difficulties of fighting on Okinawa. (U.S. Army)

Marines of the 2nd Battalion, 22rd Marine Regiment, land at Green Beach One during the opening days of the Battle of Okinawa in 1945. (U.S. Marine Corps)

Brig. Gen. Merwin H. Silverthorn, 3rd Amphibious Corps chief of staff, center, designates on a relief map a Japanese position on an Okinawa beach prior to the invasion. (U.S. Marine Corps)

Marines wade through surf over coral reef prior to the invasion of Okinawa on March 31, 1945. (U.S. Marine Corps)

Supported from the air, Marines move inland from the Okinawa beach on April 1, 1945, the beginning of the Battle of Okinawa. (U.S. Marine Corps)

Marines hurdle a stone wall as they drive across Okinawa on April 1, 1945, the first day of the Battle of Okinawa. (U.S. Marine Corps)

Marines hit Blue Beach 2 on April 1, 1945, during the first day of the Battle of Okinawa. (U.S. Marine Corps)

Tank-borne infantry moving up to take the town of Ghuta before the Japanese can occupy it in April 1945 during the Battle of Okinawa. The men are members of the 29th Marines. (U.S. Marine Corps)

Corsairs of the ''Hell's Belles'' Marine Corps fighter squadron are silhouetted against the sky by a molten lead lacework of anti-aircraft shells on April 16, 1945, during the Battle of Okinawa. This photo was made during a Japanese air raid on Yontan airfield. (U.S. Marine Corps)

Supported by bazookas, Marines assault a ridge two miles north of Naha on May 4, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

Two days after the victory in Europe was celebrated, 1st Division Marines wait on the crest of a slope while a barrage of phosphorous shells explodes among the Japanese positions on the farther incline during their drive toward Naha, the capital city of Okinawa. (U.S. Marine Corps)

Tanks moving up on the town of Naha, Okinawa, in May 1945. (U.S. Marine Corps)

Marine riflemen movie up behind flame-throwing tank on May 23, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

Maj. Gen. Lemuel C. Shepherd, Jr., commanding general of the 6th Marine Division, studies a map in April 1945 during the Battle of Okinawa. (U.S. Marine Corps)

Taking cover in the debris of the wrecked city of Naha, Marine infantrymen pick off Japanese snipers concealed in the ruins of a large building on May 23, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

U.S. Marines are pinned down behind gravestones by enemy sniper fire as they move their way through ''Cemetery Ridge," on June 1, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

Col. Allen Shapley, 4th Marine Regiment commander, points out to his officers their objectives for the big push, on the map on May 20, 1945, during the Battle of Okinawa. (U.S. Marine Corps)

A Marine lines his sights on a Japanese sniper with his ''Tommy gun'' as his companion ducks for cover during the Battle of Okinawa. The division was engaged in taking Wana Ridge before the town of Shuri. (U.S. Marine Corps)

Below Shuri Castle, on Okinawa, Marines found a Christian church whose steeple provided a snipers' nest for the Japanese. The Marines in the foreground are covering the building while a patrol comes in from the rear. (U.S. Marine Corps)

U.S. Marines fire a 105mm Howitzer in Naha, Okinawa, during the final big battle of World War II. (U.S. Marine Corps)

An F-4U of Marine Air Group 33 fires its rockets at as Japanese stronghold in southern Okinawa. (U.S. Marine Corps)

Lt. Col. William Kuratich, briefs pilots for 500-pound bomb attack against Japanese positions on southern Okinawa during the battle for the island. (U.S. Marine Corps)

A Marine-laden landing ship moves toward Iheya, Okinawa, as the land is pounded by an air assault on June 3, 1945. (U.S. Marine Corps)

Marine Corps Corsairs fly in formation during a rocket strike against Japanese positions south of the front lines on Okinawa, on June 10, 1945. (U.S. Marine Corps)