The Battle of Okinawa was the only battle fought on Japanese soil during World War II, and the fighting was so fierce that Okinawans nicknamed it the "Typhoon of Steel," or tetsu no bofu. Battle veterans returning to the island today recognize little of the Okinawa of 1945, as most of the buildings were leveled and much of the landscape was bombed and blasted away.

The Japanese Imperial Navy built the headquarters of its Okinawa district headquarters under a hill in Oroku, near Naha. Abandoned for decades after the war, the chambers have been opened to the public since the 1970s. Visitors can see the marks left on the walls by the pickaxes of the men who carved the commander's office, storerooms, bunk rooms, powder rooms, and medical rooms from the earthy hill. Blast marks from the mass suicide committed by Vice Admiral Minoru Ota and his men are visible as well. Some tunnels and rooms remain exactly as they were during the war and are off limits to visitors.

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