The Hai Van Pass — Den Mountain Pass, the Pass of the Ocean Clouds — climbs 500 metres above the sea just south of Lang Co, separating Thua Thien Hue province from Da Nang. Until the tunnel below it opened in 2005, every car, truck and motorbike heading down the coast had to crawl over the top, and the road has been beautifully empty ever since.
A motorbike or a hired car with driver is the way to do it. Stop at the old French and American military bunkers at the summit, walk a few minutes for the view back over Lang Co Bay, and then descend the southern side to look down on Da Nang and the Son Tra Peninsula. The whole loop from Lang Co takes a couple of hours. Avoid in mist or heavy rain — visibility drops to nothing and the road is slippery.