Subjects for his camera were way too many, from fishermen in boats, people at temple fairs, traders in mule and horse markets, street hawkers preparing deep-fried dough cakes and village children learning acrobatics, to bridges, wood and stone houses, monuments, towers and tombs.

"When we arrived at Gongchen Bridge, which marks the end of the canal in Hangzhou, we were both relieved and excited. We made a pact to cycle along the canal one more time after 10 years," the photographer recalls. "But life got busy and we never managed to realize that dream together."

In 2016, Liu, then 68, retraced the route they had taken 35 years ago. Shen was too old to join the cycling trip, so only a camera kept Liu company. "I found that many places and customs along the canal had changed because people's livelihood did not essentially depend on the waterway anymore," he says.

Liu is still organizing the several thousand photographs taken during his two trips. He is digitizing and labeling the significant ones, and has agreed to donate these pictures to the Capital Museum. "I want the photos to aid historical research, evoke interest and prompt conservation of the canal culture," he says.