First off, the building itself is very interesting. It is built to be as close to nature as possible with curved walls and the entrance facing east and a dome that is open to the sky.
The National Museum of the American Indian (NMAI) has one of the most extensive collections of Native American arts and artifacts in the world—approximately 266,000 catalog records (825,000 items) representing over 12,000 years of history and more than 1,200 indigenous cultures throughout the Americas. Ranging from ancient Paleo-Indian points to contemporary fine arts, the collections include works of aesthetic, religious, and historical significance as well as articles produced for everyday use
We ate lunch at their restaurant, the Zagat rated Mitsitam Native Foods Cafe. It is a cafeteria style restaurant that serves foods based on the indigenous foods of the Americas. It was hard to choose, but I got Salmon with a tapenade sauce with a wiild rice salad and Joe got Buffalo Loin with potatoes. Both were very good. We sat at a nice spot by a waterfall treatment,
More curvature inside as you can see below.
The bottom floor has a large area where Native American people sell their art, jewelry, etc. I bought a silver ring. There was also music which we listened to from the floor above.