At the Museum of African American History and Culture.
I much preferred the history part of this museum. You take an elevator down three stories below ground and work your way back up along a ramp while going from the roots of slavery in Africa through its establishment in the colonies, the Civil War, Reconstruction, and Jim Crow to the present day. I was completely immersed in the experience -- it was shattering -- and honestly I probably should have just left afterwards.
Instead I took the escalator up to the culture floor. And that's the problem right there -- trying to fit it all on one floor. The music alone needs its own museum, and they try to cover theater, fashion, art, movies and television as well. I'm not sure how you could present all of that material without it feeling like the most glancing overview -- it was simultaneously too much and not enough.
And honestly, the only way to appreciate music is to listen to it, not look at costumes and awards in a glass case.