North Korea, also known as the Democratic People’s Republic of Korea, is a country in East Asia. South Korea (Republic of Korea) is located adjacent to the country and separated from the northern side of the peninsula by a staunchly guarded wall. Kim Jong-un is the Supreme Leader of North Korea. The nation is often referred to a rogue state that frequently threatens the United States with military action. After World War II, the United States and Russia separated the Korean peninsula into two parts. After reunification between the two areas failed in 1948, separate governments were established. An invasion of the south launched by the north in 1950 started the Korean War. A cease-fire was signed, and both countries were accepted into the U.N. in 1991.