Tam Duong is the obscure town between Sapa and Lai Chau. While the town is nothing special, it's the usual lunch stop of travelers making this trip by 4WD. When the road gets particularly bad after a heavy rain, the 'lunch stop' may turn into an ' overnight stop' (or even the 'turn-around point').
The local market, about midway through town on National Highway 12, is worth a visit. The majority of people are colorful Montagnards from nearby villages, although the ethnic - Vietnamese are still the largest single group. If you are not rushing to get to Sapa or Lai Chau, it is a definite possibility to base yourself in Tam Duong for a few days and explore the surrounding area.
The drive from Tam Duong to Sapa along Route 4D, Threading the Fan sipan Mountain Range and the China border, is perhaps the most beautiful stretch of road in Vietnam.