Korea refers to South Korea and North Korea together, which were a unified country until 1948. It is situated on the Korean Peninsula in East Asia, bordering China to the northwest and Russia to the northeast. It is populated by a homogeneous ethnic group, the Koreans, who speak a distinct language (Korean).
Korea was partitioned into two halves following World War II. South Korea, supported by the United States, is now a capitalist liberal democracy, and sometimes referred to simply as "Korea". North Korea, supported by the former Soviet Union, remains a Communist state, often described as Stalinist and isolationist.
Korea is located on the Korean Peninsula in North-East Asia. It is bound by two countries and three seas. To the northwest, the Yalu River separates Korea from China and to the north, the Tumen River separates Korea from Russia. The Yellow Sea is to the west, the South China Sea is to the south, and the Sea of Japan (East Sea) is to the east of Korea. Notable islands include Jeju-do, Ulleung-do, and Liancourt Rocks (Dok-do).
The southern part and western part of the Korean mainland have well developed plains, while the eastern and northern parts are mountainous. The highest mountain in Korea is Mt. Baekdu (2744m, Changbaishan in chinese). The border with China runs through the mountain. The southern extension of Mt. Baekdu is a highland called Gaema Gowon. This highland was mainly raised during the Cenozoic orogeny and partly covered by volcanic matter. To the south of Gaema Gowon, successive high mountains are located along the eastern coast of the Korean Peninsula. This series of mountains is named Beakdudaegan. Some significant mountains include Sobaeksan (2,184 m), Baeksan (1,724 m), Geumgangsan (1,638 m), Seoraksan (1,708 m), Taebaeksan (1,567 m) and Jirisan (1,915 m). There are several lower, secondary mountain series whose direction is almost perpendicular to that of Baekdudaegan. They are developed along the tectonic line of Mesozoic orogeny and their directions are NW, NWW.
As opposed to the old mountains on the mainland, some important islands in Korea were formed by volcanic activity in the recent Cenozoic. Jeju Island, situated off the south coastline of the Korean Peninsula, is a large volcanic island whose main mountain is Mt. Halla (1950 m). Ulleung-do and the Liancourt Rocks (Dok-do) are volcanic islands in the East Sea (Sea of Japan), whose composition is more feslic than Jeju. The volcanic islands tend to be younger as one moves westward.
Because the mountainous regions are biased toward the eastern part of the peninsula, the main rivers tend to flow to westwards. Two exceptions are the southward-flowing Nakdong and the Seomjin River. Important rivers running westward include the Yalu, Cheongcheon River, Daedong River, Han River, Geum River, and Yeongsan River. These rivers have vast flood plains and they provide an ideal environment for rice cultivation.
The southern and southwestern coastline of the Korean Peninsula is a well-developed Lias coastline. It is known as Dadohae in Korean. Its complicated coastline provides mild seas, and the resulting calm environment allows for safe navigation, fishing, and seaweed farming. In addition to the complex coastline, the western coast of the Korean peninsula has an extremely high tidal amplitude (at Incheon, around the middle of the western coast, it is as high as 9 m). Vast tidal flats are developing on the south and west coastline of the Korean Peninsula.
