Introduction to the West Sea Gate: The West Sea Gate is a large-scale water conservancy project built at the entrance of the Datong River to the West Sea of ​​Korea. It can prevent seawater intrusion disasters, preserve fresh water, regulate water traffic, and communicate with land traffic. . The main construction force was 40,000 People's Army soldiers. Construction started in 1981 and was completed in 1986. North Korea claimed that the project cost 4 billion US dollars. Many foreign heads of state and important foreign guests have visited here.