Dalian boasts its convenient communication and telecommunication networks. It is a hub of the comprehensive transportation system with a powerful capacity either through the sea, land or air. The Dalian Port is a world-known deep and non-frozen harbor with more than 70 berths, including 40 with above 10,000 tons berthing capacity, connecting with over 300 ports in 160 or more countries. The port it´s the largest transient terminal for grains and petroleum of China. Dalian is linked with the well-developed highway networks, among which the most significant ones are Shenyang-Dalian Expressway, the earliest of its kind in China; Dalian-Zhuanghe and Dalian-Lushun highways. In the city proper, there are many convenient public transportation lines with light rail wagons, trolley buses and buses; and the most advanced urban traffic controlling system in the world. Dalian Zhoushuizi International Airport can be landed with Boeing 747 and has opened 86 domestic or international air routes.