The road between Sapa and Lai Chau crosses the Tram Ton Pass on the northern side of Mt Fansipan, 15km from Sapa. At 1900m it's Vietnam’s highest mountain pass, and acts as a dividing line between two climatic zones. The lookout points here have fantastic views in clear weather.
On the Sapa side it’s often cold and foggy, but drop a few hundred metres onto the Lai Chau side and it can be sunny and warm. Surprisingly, Sapa is the coldest place in Vietnam, but Lai Chau can be one of the warmest.
Most people also stop at 100m-high Thac Bac (Silver Waterfall, admission 20,000d), 12km from Sapa. A one-way/return xe om here costs 80,000/150,000d.