Constructed during the rule of Queen Seondeok (27th ruler of the Silla Dynasty, from 632 to 647), Cheomseongdae is regarded as Asia’s finest observatory with height of 9.17 m and base diameter of 5.17 m. This circular stone building is made by piling a total of 361 pieces of stone brick measuring 30 cm high; from the bottom to the top square-shaped roof are 28 layers, each of which bears a high-level symbolic meaning. The size of the diameter making up each stone layer decreases as it goes up, creating a superbly elegant curved line. The record in “the Heritage of the Three States” stating that a man went up and down the observatory to observe stars coincides with the state of the actual building. Cheongseongdae is designated as Natural Treasure No. 31.

Address : 169-5, Cheomseong-ro, Gyeongju-si, Gyeongsangbuk-do, Korea