This museum has its entrance just to the north of Sto Domingo churchs entrance. It is on the same plaza as the church and part of the same building, the attached old convent building. You might not realize the entrance is there at first, although there is a banner (or was in December 2007) inside the small gated area. (This museum is also called or was call the Regional museum of Oaxaca.  )The museum is a comprehensive history of Oaxacan culture from prehistoric times to the present. In fact there is almost too much information to take in. If you go to Monte Alban and are interested in archaeology, you will want to see the contents of Tombe 7 and others that are on display here in the Museo de las Culturas de Oaxaca. There are audio tours available in English and Spanish, but  given the surfeit of information already in the museum, some might feel the audio tour is too much to take in. However, this is a personal preference. The audiotour was easy to use and informative. The museum itself is mainly located on the upper floors, and has gorgeous views of Oaxaca from the many windows off the hallways . The views themselves are worth the price of admission. You can also see into the ethonobotanic garden that is a separate section of the Sto Domingo complex and has a separate tour -to the east (on Reforma). The museum has , besides displays of artifacts of all kinds,  quite interesting videos in various rooms showing everything from old films of Mexico to interviews with people working the land in the pueblos, describing how they work together. The museum also has a nice gift shop with such things as CDs of traditional Mexican music and indigenous music, as well as postcards, books, tshirts and other souvenirs. Since there are so many handicrafts everywhere in Oaxaca, most of the handicrafts sold may seem superfluous, but other things, such as the musical CDsand books on Oaxaca are well worth checking out.  Of all the museums in Oaxaca, this might be the most important to visit if you want to learn about Oaxacan history and society.