In 1945, ground battles in Okinawa and the atomic bombing of Hiroshima and Nagasaki were followed by a radio broadcast in which the emperor announced Japan's surrender. Japan was then occupied for eight years by US-led forces. During this period, the country became increasingly democratic. Mass media that had toed the military line before and during the war became a tool to promote democracy. The airwaves were opened up; people on the street were interviewed and even showed off their singing skills. People who had starved in the ruins in the immediate aftermath of World War Two also witnessed steady reconstruction thanks partly to an economic boost from the Korean War. In 1951, the signing in San Francisco of the Treaty of Peace with Japan was followed by the signing of the Security Treaty Between Japan and the United States of America. During the Cold War, Japan returned to the international community as an ally of the West.