The Korean peninsula is largely mountainous; the principal
series of ranges, extending along the east coast, rises (in the
northeast) to 9,003 ft (2,744 m) at Mt. Paektu (Baekdu), the
highest peak in Korea. Most rivers are relatively short and many
are unnavigable, filled with rapids and waterfalls; important
rivers, in addition to the Yalu and Tumen, are the Han, the
Geum, the Taedong (Daedong), the Nakdong, and the Seomjin. Off
the heavily indented coast (c.5,400 mi/8,690 km long) lie some
3,420 islands, most of them rocky and uninhabited (of the
inhabited islands, about half have a population of less than
100); the main island group is in the Korean Archipelago in the
Yellow Sea. The climate of Korea ranges from dry and extremely
cold winters in the north to almost tropical conditions in parts
of the south. Many Koreans are Buddhists or Confucianists,
although the people tend to be eclectic in their religious
practices. Korean Confucianism, for example, has developed into
more of an ethical system than a r