Nearly everyone we spoke to prior to getting to Hanoi recommended one place to visit: the Museum of Ethnology. It is a modern museum around a 7km taxi ride from the Old Quarter. On display are artifacts and information about the many different peoples who make up the population of Vietnam.
Vietnamese Snake Puppet
Standard load for a Vietnamese bike
Even better is outside in the courtyard. The museum actually got members of each group to come to Hanoi and build a traditional house of their people. You can walk around these to get a great feel for how these different tribes live. We have added our voices to those who highly recommend a visit!
The traditional houses were all constructed by their tribes
Even the interiors were complete as per each tribes traditions
Some of the houses were enormous!
The wooden roof of one of the houses