The Pacific Theater of Operations was located in the Pacific, and it included all areas in the Pacific Ocean that were controlled by either Allied or Japanese forces. After Pearl Harbor, on December 7, 1941, the Allies started sending forces into the Pacific region in order to repel the Japanese. Though the Japanese initially had success in the war, the Battle of the Coral Sea, and the Battle of Midway, turned the tide for the Allied forces in the Pacific Theater. From that point forward, the Allied forces began to push back the Japanese lines through a series of land and sea battles. These sea battles were fought using ships, submarines, and large numbers of aircraft. The ground troops invaded the many islands that were held by the Japanese in the area. The many ground campaigns such as the Gilbert and Marshall Islands campaign, The Mariana and Palau Islands campaign, Iwo Jima, and Okinawa, helped the United States to win the war in the Pacific. After dropping two atomic bombs on Japan, the United States accepted the unconditional surrender of Japan on August 15, 1945.