South Korea, officially known as the Republic of Korea is an East Asian country occupying the southern half of the Korean Peninsula. To the north, it is bordered by North Korea (Democratic People's Republic of Korea), with which it was united until 1945. To the west, across the Yellow Sea, lies China and to the southeast, across the Korea Strait, lies Japan. The Republic of Korea in Korean means "The Great Nation of the Korean People" and is sometimes referred to as the "Land of the Morning Calm", originating from the peaceful Joseon Dynasty. The capital and largest city of South Korea is Seoul, the world's 2nd largest metropolitan city. The official language of South Korea is Korean and is currently the 10th most spoken language in the world.