L1 | Why is Dujiangyan still operational after more than two thousand years, without relying on a dam across the river?

What Dujiangyan has truly sustained for over two millennia is perhaps not merely an engineering project, but rather a way for humanity and nature to coexist over the long term.

https://video.wixstatic.com/video/347763_adc16b85299c4a4981b967e859c1d51e/1080p/mp4/file.mp4