Cheomseongdae is an astronomical observatory in Gyeongju, South Korea. Cheomseongdae means star-gazing tower in Korean. Cheomseongdae is the oldest surviving observatory in East Asia, and one of the oldest scientific installations on Earth. It dates to the 7th century to the time of kingdom of Silla, which had its capital in Gyeongju. Cheomseongdae was designated as the country's 31st national treasure on December 20, 1962. The tower is 5.7 meters wide at the base and 9.4 meters tall, and filled with earth up to the level of the window. Its construction style parallels that used at the Bunhwangsa Temple in Gyeongju.