evidence: South Korea,[c] officially the Republic of Korea (ROK),[d] is a country in East Asia. It constitutes the southern part of the Korean Peninsula and borders North Korea along the Korean Demilitarized Zone; though it also claims the land border with China and Russia.[e] The country's western border is formed by the Yellow Sea, while its eastern border is defined by the Sea of Japan. South Korea claims to be the sole legitimate government of the entire peninsula and adjacent islands. It has a population of 51.96 million, of which half live in the Seoul Capital Area, the ninth most populous metropolitan area in the world. Other major cities include Busan, Daegu, and Incheon. [...] South Korea occupies the southern portion of the Korean Peninsula, which extends some 1,100 km (680 mi) from the Continental and East Asian mainland. This mountainous peninsula is flanked by the Yellow Sea to the west and the Sea of Japan to the east. Its southern tip lies on the Korea Strait and the East China Sea. The country, including all its islands, lies between latitudes 33° and 39°N, and longitudes 124° and 130°E. Its total area is 100,410 square kilometers (38,768.52 sq mi).[6]