Cheomseongdae
| Cheomseongdae | |
|---|---|
| Cheomseongdae (2009) | |
| General information | |
| Town or city | Gyeongju | 
| Country | South Korea | 
| Coordinates | 35°50′05.0″N 129°13′08.4″E / 35.834722°N 129.219000°E | 
| Completed | 7th century | 
| Height | 9.17 m (30.1 ft) | 
| Designations | |
| Official name | Gyeongju Historic Areas | 
| Criteria | Cultural: (ii), (iii) | 
| Designated | 2000 | 
| Reference no. | 976 | 
| Official name | Cheomseongdae Observatory, Gyeongju | 
| Designated | 1962-12-20 | 
| Korean name | |
| Hangul | 첨성대 | 
| Hanja | 瞻星臺 | 
| Revised Romanization | Cheomseongdae | 
| McCune–Reischauer | Ch'ŏmsŏngdae | 
Cheomseongdae (Korean: 첨성대; Hanja: 瞻星臺; lit. star-gazing tower) is an astronomical observatory in Gyeongju, South Korea. Cheomseongdae is the oldest surviving astronomical observatory in Asia, and possibly even the world. It was constructed during the Silla period, during the reign of Queen Seondeok (r. 632–647 AD). Cheomseongdae was designated as the country's 31st national treasure on December 20, 1962. It is part of Gyeongju Historic Areas, a UNESCO World Heritage Site.