When I started traveling north from Ho Chi Minh City, the first stop on most of the "open bus" tickets are in Mui Ne.  It's about a 4-5 hour bus ride north of Ho Chi Minh, located along the east coast.   A lot of backpackers and other travelers stop here because of the famous sand dunes - which is just one of the sights to take in.    Though obviously I agree that the sand dunes are a "must-see" in Mui Ne, there are a few other things worth grabbing your attention.