South Korea (ˌsaʊθ kəˈriə), officially the Republic of Korea (ROK, Hangul: 대한민국, Hanja: 大韓民國, pronounced [tɛːhanminɡuk̚]), is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China (Mainland China) to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China (Taiwan) to the south. South Korea lies in a humid continental and humid subtropical climate region with a predominantly mountainous terrain. Its territory covers a total area of 99,392 square kilometers and has a population of almost 50 million. The capital and largest city is Seoul, with a population of 10,421,782.