Visitors gaze at the painting Along the River During the Qingming Festival at the Palace Museum in Beijing on Sep 8, 2015. [Photo/IC]

Booming industries and trade led imperial authorities of the Northern Song Dynasty (960-1127) to build open communities in cities. This is reflected in the famous painting,Along the River During the Qingming Festival, which showed people's lives in the capital city of the Northern Song.

Imperial authorities never built closed communities since the Northern Song Dynasty, until the Qing Dynasty (1644-1911) when authorities built fences to separate communities at its early stage to stabilize the control of the country. But authorities stopped fencing communities in the middle of Qing Dynasty.