Kaesong Cheomseongdae: Astronomical tradition behind Korea's greatest star map

In April, I stood before the Goryeo Kingdom's Cheomseongdae in Kaesong, once known as Hwangdo, the imperial capital of Goryeo, and now one of the UNESCO World Heritage Historic Monuments and Sites in Kaesong, North Korea.

Unlike the towering 9.17-meter stone Cheomseongdae observatory built during the Silla Kingdom in Gyeongju, Kaesong's Cheomseongdae appears almost understated, standing only 2.47 meters tall.

Yet appearances are deceiving.

Four square granite pillars, together with a central sup ...