Seoul Special City, is the capital and largest metropolis of South Korea. A megacity with a population of over 10 million, it is the largest city proper in the OECD developed world. The Seoul National Capital Area is the world's second largest metropolitan area with over 25 million inhabitants, which includes the surrounding Incheonmetropolis and Gyeonggi province. Almost a quarter of South Koreans live in Seoul along with over 275,000 international residents.