Kaifeng

Kaifeng is a city in the Henan province of the People's Republic of China, located along the Huang He, 70 km from Zhengzhou[?], the provincial capital. Population: 4.3 million.

Kaifeng was a capital of the Northern Song, during that time, having a population of over million living both inside and outside walls. Typhus was an acute problem of the city.

In the earlier Sui dynasty, the Grand Canal was built from Kaifeng to Hangzhou, linking the Yellow River and the Yangzi. Extensions to the system effected an even greater navigable length.