Cheomseongdae Observatory

Cheomseongdae 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 in the 7th century in the kingdom of Silla, whose capital was Seorabeol, or present-day Gyeongju. Cheomseongdae was designated as the country's 31st national treasure on December 20, 1962. It forms a UNESCO World Heritage Site along with other Gyeongju Historic Areas.

Modeled on Baekje's Jeomseongdae, which now exists only in historical records, the Cheomseongdae influenced the construction of the Japanese Senseidai observatory in 675, and Duke Zhou's observatory in China in 723.