Seoul is the capital and largest metropolis of South Korea. A megacity with a population of more than 10 million, it is the largest city proper in the developed world. The Seoul Capital Area, which includes the surrounding Incheon metropolis and Gyeonggi province, is the world's second largest metropolitan area with over 25.6 million people, home to over half of South Koreans along with 632,000 international residents. During the Korean War, Seoul changed hands between the Chinese-backed North Korean forces and the UN-backed South Korean forces several times, leaving the city heavily damaged after the war. One estimate of the extensive damage states that after the war, at least 191,000 buildings, 55,000 houses, and 1,000 factories lay in ruins. In addition, a flood of refugees had entered Seoul during the war, swelling the population of Seoul and its metropolitan area to an estimated 2.5 million, more than half of them homeless.