This observatory was built during the reign of the Silla Queen Seondeok (632-647 AD). This is the oldest astronomical observatory in East Asia which consists of 26 steps of 30cm high stones placed above double stylobates. Its exact dimensions are 5.17 meters in diameter and 9 meters in height and is made of granite stones witha stoen base measuring 5.35 meters.
At the top, the square stones are arranged in the shape of the Chinese letter for "well". Every part of the building from its structure and composition of each stone contains symbolical meaning. It is filled with various scientific yet mysterious points, such as the fact that the stones that make up the letter for well at the top of the observatory are exactly the length of the stylobate.