The province has a fairly well-developed transport and communications network. Jilin has four airports “ in Changchun, Jilin, Yanji and Liuhe “ offering links to domestic and international air routes. There are more than 120 rivers in the province, including Songhua, Liaohe and the Yalu river systems. Inland water transport is available between April and November along the Songhuajiang River . The Jingha railway line (Beijing to Harbin) is the most important trunk line in the province and the railway system handles more than two thirds of the province 's cargo transport. The CIS and Europe are also accessible by railway via Harbin and Manzhoul. Jilin also has a number of scientific research institutions, colleges and universities.