The Desert Museum is barely visible directly in the middle of the photo (nestled in the hills). I believe these are the off exhibit facilities as visitors do not get a view of this valley from the grounds (this valley would be east of the grounds, though of course when I took this photo I was on the other end looking west). Instead, you get a very nice view from the grounds looking south, which would be left of this photo (and behind the rolling hills).
Normally this view is a pale green, but right now (early May) it is yellow because the palo verde trees are in bloom. This entire area is Tucson Mountain Park, which is a large natural area protected by the county (Desert Museum leases land from them). Just beyond the Museum the county land blends seamlessly with federally protected land in the form of Saguaro National Park west (there is also a Saguaro National Park east on the opposite side of Tucson).
