This week, North Korea marked 70 years of communist rule.
The government was established with the help of the Soviet Union at the end of World War Two.
North Korea has been isolated ever since, sealed-off from the South by a heavily-guarded barrier known as the DMZ or Demilitarized Zone.
But for Koreans on both sides, the divide is not just physical. There's now a wide cultural gap as well.
Dave Kang, director of the USC Korean Studies Institute, joined the show to explain more.