The Koryo Museum is a relatively new building in Kaesong, North Korea. By relatively new, I mean it was built in 1987. The actual museum comprises 12 buildings along with 6 accessory buildings of Songgyungwan. Songgyungwan itself is an ancient, prestigious Confucian academy, but that's a story for another time.
The museum itself holds a treasure trove of priceless relics from the Koryo Dynasty, although many of the relics are actually copies with the originals safely stored away in the Korean Central History Museum in Pyongyang. The Koryo Dynasty is the dynasty in Korea that immediately preceded the Joseon Dynasty. The dynasty's conclusion is marked by the assissination of the Confucian scholar and statesman, Jeong Mong-ju. He was killed on the nearby Sonjuk Bridge, where you can still visit today to see the supposedly blood stained stone from his death.