Dien Bien Phu is the capital of the province with the same name. It was the location of a battle which took place in Tonkin from 20 November 1953 to 7 May 1954 against the French Union forces. It is considered to be the place of victory for national liberation.
Blue Hmong, Red Dao, Black Lolo... The ethnic minority groups living in the misty mountains of Northern Vietnam form a true patchwork quilt of different cultures. Going to meet them is guaranteed to be an intense trip that would only equal coming into contact with other ancestral peoples.
As a pro of organised trips or guided visits, your next destination is Vietnam, you aren't going to break your habits are you? So plan to explore the country with a local French speaking guide. It's also good to know about guided visits of Vietnam with an expert on the area.