Hai Van Pass is a mountain pass on National Road 1A in Vietnam. It traverses a spur of the larger Annamite Range that parallels the South China Sea. Translated into English, Hai Van means 'ocean clouds', and thus the pass is known for its misty vapors rising from the sea, reducing visibility. Historically, the pass has long been an obstacle on the north-south road of Vietnam and was an physical division between the Kingdom of Champa and Dai Viet. The twisting road on the pass has long been a challenge for many Vietnamese drivers.