Cheomseongdae is an
astronomical observatory in
Gyeongju, South Korea. It is the oldest surviving astronomical observatory in Asia. It was constructed in the 7th century in the kingdom of
Silla. Cheomseongdae was designated as South Korea's
31st national treasure in 1962. Modeled on
Baekje's Jeomseongdae, which now exists only in historical records, Cheomseongdae influenced the construction of a Japanese observatory in 675, and Duke Zhou's observatory in China in 723.
Photograph: Matt and Nayoung Wilson