Rapeseed flower fields have long been a well-known tourist attraction in the city of Xinghua, east China's Jiangsu Province. The rapeseed plants here grow in "Duotian," a field of island-like structures that scatter across shallow lakes.

Known as the Xinghua Duotian Irrigation and Drainage System, it remains a contributor to local flood control, drought prevention, ecological agriculture and tourism. Covering an area of over 52 square kilometers, the system is a composite of agriculture, forestry and fishery, which has important value in local agricultural production and sustainable development, inheritance of farming culture, and protection of rural ecological environment. In October 2022, the system received a World Heritage Irrigation Structures (WHIS) designation, which aims to protect and promote irrigation projects of historical and scientific value.