Here you can meet ethnic minorities like Black Hmong, Red Dao, Zay, Tay...
and do some nice hiking across rice paddies and corn field. Definitely a good spot on condition that you choose the right tour guide (see below).
How to get there?
From Hanoi, you can take a sleeping bus or a night train (more expensive but more comfortable).
With the sleeping bus you'll arrive directly in Sapa instead of the train which stops in Lao Cai (then, take a shuttle from Lao Cai to Sapa - around 1 hour drive).
Tour guide to explore Sapa and meet ethnic minorities
You can book a tour (from 1 to few days) in Hanoi or directly in Sapa. You'll find heaps of agencies and sometimes it's difficult to make a choice. Be careful, most of them propose some very touristic tours with a big group!
I recommend Vietnam Nomadtrails agency http://www.vietnamnomadtrails.com/ if you wanna get off the beaten track. I booked with them 3 days and 2 nights and this hiking will remain forever in my memory.
Price : 110 US dollars pax for 1 (english) guide and 2 persons (all included except the transport from/to Hanoi).
Spectacular views over rice paddy and corn field
Ethnic minorities villages
We visited some villages inhabited by ethnic minorities: black Hmong, Dao, Zay and Tay.
Our guide told us a lot of stories about theses minorities, their daily life, their differences, some things about their clothes, legends, customs.... It was really fascinating and enriching.
First day: overnight in a typical Red Dao house
Second day: overnight in a Zay family
You can help them to prepare the diner and learn how to cook somes traditional dishes.
For the 2 homestays: very good food and hearty meal. The family will invite you for drinking rice alcohol and you can't refuse it, it's traditional (so watch out, hangover the day after).
During theses 3 days hiking we saw a lot of children, buffalo, pigs, dogs.... on the road.
Theses tribes are really poor (especially Hmong people) and most of the children don't go to school so they can not even speak vietnamese, only their dialect (which is different between the tribes).
At times it's really hard to see that much poverty. The second day, during the lunch (pic nic), 9 children came to us. They didn't ask anything, just looked at us while we were eating our sandwich. Obviously we shared all our food with them.
If you can, buy some candies and other snacks before the trek to give it out to the children you'll bump into on the road.
Furthermore, if you wanna buy some typical souvenirs, better to buy it in theses villages which really need money than in the market in Bac Ha.
Sapa is definitely one of the best place to see in Vietnam. Don't miss it!