The Beijing-Hangzhou Grand Canal Museum explains the waterway that tied Hangzhou to northern China for centuries. Exhibits cover canal engineering, cargo, locks, waterside towns, and the imperial grain-transport system that made the canal one of China's great pieces of infrastructure.
It is most rewarding if you have already walked part of Hangzhou's canal district, because the displays give the quiet towpaths and bridges a larger frame. The museum is not as essential as West Lake, but it adds useful historical depth to a city often reduced to scenery.