Hai Van Pass (496) north of Da Nang is the second highest pass in Vietnam, next after Heavens Gate near Sapa. It is a natural boundary between the subtropical North and tropical South Vietnam. During the French occupation and the Vietnam War, the pass played an important military role and to this day you can still see some bunkers at the top. Due to the special weather conditions, the view is rarely clear in both direction when reaching the top and the whole peak is often covered in clouds, hence the name Hai Van (meaning "Ocean Clouds"). In 2005, the Hai Van Tunnel opened, cutting straight through the mountain and eliminating the scenic, though scary, hairpin route over the pass.