Middle AgesTechnology Su Song's astronomical clock tower 1092Notable A water-powered clock tower with an escapement mechanism. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → First fired clay figures → First pottery → Copper smelting → Bronze Age begins → Shang dynasty → Zhou dynasty and the Mandate of Heaven → Spring and Autumn period → Legalism (Shang Yang) → Qin unifies China → Han dynasty → Sui reunifies China → Imperial examinations → Tang dynasty → Song dynasty → Su Song's astronomical clock tower Community notesLoading notes… Learn more ranked by votesBookJoseph Needham, Wang Ling and Derek J. de Solla PriceHeavenly Clockwork: The Great Astronomical Clocks of Medieval China ↗Editor's pickVideoSearch on YouTubeSu Song astronomical clock tower ↗Editor's pick