How did it start?
Korea was originally one solitary nation. In the early 1900's, it was claimed by Japan. Following WWII, Japan surrendered to the Allied Forces (the U.S. and our allies in the war). As part of the spoils of war, the U.S. and Russia decided they would split the Korean Peninsula in two. The U.S. took the southern portion, and Russia took the north. The 38th parallel became the dividing line. This was supposed to be a temporary measure. Clearly, that didn't work so well...
Then what?
The Soviets set up Kim Il Sung as a "puppet leader" over their half of Korea. He ended up in power for decades and is who created the isolationist attitude in the country. He took it upon himself to create the title "Supreme Leader" and to rewrite the history of the country based on his life. Not surprisingly with such a leader, the northern portion started getting power hungry and wanted more control over the entirety of the peninsula. With Russia and China on their side, the north decided to invade the south. The U.S. came to the aid of South Korea, and the result was a war that is technically still ongoing in which millions of people have been killed. Tensions are still incredibly high along the border, or the DMZ (demilitarized zone). When Sung died in the 90's, Kim Jong Il took over a country that was devastated by famine and a suffering economy... So he started boosting the nuclear program. Kim Jong Un is the most recent ruler. Continuing human rights abuses and threatening the world seem to be his favorite past times.
And now?
North Korea is on most of the world's watch list. The international community is at its wits end trying to figure out a way to stop the threats and abuses. The citizens of North Korea are suffering. They starve and are abused every day. Every aspect of their lives is determined by the government. The only education they have access to is provided by the government, and it's entirely propaganda. They are publicly executed, sold as slaves, or thrown into labor camps.
It's unclear what the future holds for the U.S. and North Korea. The country is so locked down it is hard to say what the country actually possesses in weapons. The UN is pursuing sanction options, and most of the international community is getting on board with taking some action to help the problem.
