Cheomseongdae (Chomsongdae) is a 7th-century CE observatory tower located in Gyeongju, the capital of the Silla Kingdom of ancient Korea. It is the oldest surviving astronomical observatory in East Asia and is listed as no. 31 on the official list of National Treasures of Korea.

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  • 57 BCE - 918 CE
    The Silla Kingdom rules in Korea, first as one of the Three Kingdoms and then alone from 668 CE.
  • 632 CE - 647 CE
    Reign of Silla queen Seondeok in south-eastern Korea.