Dujiangyan irrigation system belongs to the years before the Common Era — dated here to c. 256 BCE at Sichuan, China. The date is a scholarly centre of gravity, not a foundation-stone timestamp.
Li Bing split the Min River without a dam, watering the Chengdu Plain for 2,300 years — a living Warring States machine.
How it was made
Fish-mouth levee, flying sand weir, and Bottle-Neck Channel. Maintenance is the monument.
Why it still counts as a wonder
It never needed a Greek list to be a wonder: the labour, the alignment, or the survival is enough.
UNESCO calls it a wonder of ecology and engineering. It still feeds rice.
On dating
BCE in this series means years before the traditional birth of Christ, counted backward. A monument listed as c. 256 BCE may have been founded earlier, rebuilt later, or famous only in one phase. Where ancient writers disagree — as they do for Babylon’s gardens — we say so.
This is story 87 of 100 in The Trend Ledger’s illustrated desk on world wonders raised before the Common Era.