The Kaesong Chomsongdae Observatory is located in Songak-dong, Kaesong, North Korea. It was an astronomical observatory during the Koryo period. Now only a granite platform remains, the sides of which coincide with the main cardinal points. The structure is made of over 360 granite stones, indicative of the passage of one year. It was used for astronomical and meteorological observation, with equipment at the top used in the observation of changing weather and the movement of celestial bodies.