Su Song builds astronomical clock

1090

The Song polymath Su Song began construction of a thirty-foot-tall water-driven clock tower in Kaifeng, with an armillary sphere, celestial globe, and mechanical puppets striking bells to mark the hours. It was the most sophisticated astronomical mechanism ever built in any civilization to that point in human history. The clock's escapement mechanism anticipated European horological innovations by three centuries, though the knowledge was lost when Kaifeng fell.