Hai Van Pass or Sea Clouds Pass offers an impressive landscape of verdant mountains and clear blue skies, overlooking Da Nang City, Tien Sa Port, Son Tra Peninsula, and South China Sea. Crossing over a spur of Truong Son mountain range between Thua Thien-Hue Province and Da Nang City, it stands at 500m above sea level, making it the highest pass in Vietnam.
The 25 kilometre-long mountain pass is popular amongst thrill-seeking motorcyclists due to its winding roads, sudden curves and blind corners, while its lookout point offers gorgeous views of Da Nang Bay.
The pass also hosts the ancient Tran Dynasty’s Hai Van Gate, Hai Van Tunnel (the longest in ASEAN), wartime gun towers, and a decrepit French-built fort that was later used as a bunker by South Vietnamese and US armies during the Vietnam War. Prior to the construction of the Hai Van Tunnel, the mountain pass was notorious for its fair share of fatal accidents – look out for small altars set along the roadside that are dedicated to perished victims. http://www.vietnam-guide.com/da-nang/attractions/hai-van-pass.htm