For 74 consecutive days, the Allies bombarded Iwo Jima before 30,000 U.S. Marines went ashore on February 19, 1945. Before the bombardment began, the Japanese had 23,000 elite forces in defense of the fortress. Four days into the struggle, which was some of the war's bloodiest, they reached the peak of Mount Suribachi. The island was secured by mid-March. The Japanese lost 21,000, all killed. Only 200 prisoners were taken. Iwo Jima represented a valuable refueling base for the Allies, or an emergency landing field for heavy bombers on their way to or from bombing runs over Japan.