North Korea’s troubled history with the U.S.—and the world—goes back to the end of World War II. In 1945, the Korean Peninsula, which had been occupied by Japan since 1910, was divided into two zones.
The North, led by Kim Il Sung (Kim Jong Un’s grandfather), established a Communist government backed by the Soviet Union and China. (Under Communism, the government owns all land and businesses, and individual freedom is limited.) South Korea became a democracy and a key U.S. ally.
In 1950, North Korea invaded the South, starting the Korean War. An international coalition led by the U.S. came to the South’s defense. In 1953, both sides signed an armistice to end the conflict. By then, about 34,000 Americans had been killed.
The agreement established a 2.5-mile-wide demilitarized zone (DMZ) separating North and South Korea at the 38th parallel, the line of latitude at 38 degrees North. Decades later, the two nations have yet to sign a formal peace treaty, and they remain hostile to each other.
Today, South Korea has the 13th-largest economy in the world. North Korea, meanwhile, has become one of the poorest countries on Earth. The nation relies on China—its main ally and biggest trading partner—for much of its food and electricity.