Cheomseongdae is one of the oldest structures in Korea. This unique bottle-shaped building was built in 647 during the reign of Queen Seondeok of the Old Silla kingdom and was used as an astronomical observatory. The base is 5.7 meters wide (17 ft) and stands 9.4 meters (31 ft) tall. Twenty-seven layers of granite cut like brick support the upper bars of stone that form the top platform.
The granite-brick construction is similar to the method used at Bunhwangsa temple, which developed from contact with Tang dynasty China.
Cheomseongdae is one of the oldest scientific installations on earth.