North Korea (officially the Democratic People's Republic of Korea), is a country in East Asia, in the northern part of the Korean Peninsula. The capital and largest city is Pyongyang. North Korea shares a land border with China to the north and north-west, along the Amnok (Yalu) and Tumen rivers. A small section of the Tumen River also forms North Korea's border with Russia to the northeast. The Korean Demilitarized Zone marks the boundary between North Korea and South Korea. The legitimacy of this border is not accepted by either side, as both states claim to be the legitimate government of the entire peninsula.
The Empire of Japan annexed Korea in 1910. After the Japanese surrender at the end of World War II in 1945, Korea was divided into two zones by the United States and Soviet Union, with the north occupied by the Soviets and the south by the Americans. Negotiations on reunification failed, and in 1948 two separate governments were formed: the Democratic People's Republic of Korea in the north, and the Republic of Korea in the south. The conflicting claims of sovereignty led to the Korean War in 1950. The Korean Armistice Agreement in 1953 led to a ceasefire, but no peace treaty was ever signed. Both states were accepted into the United Nations in 1991.