Seoul officially the Seoul Special City — 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.[5] 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,[6] home to over half of South Koreans along with 632,000 international residents.