Probably pretty dark, except by the entrance, which is where'd they be. The front wall of the entrance is a big glass piece, allowing the light of day into the foyer, but the back wall prevents it from illuminating the rest of the museum except when they want it to be lit. It wouldn't be completely dark, since there are skylights throughout the building, but with the tour, most of them are closed, letting only a little light in.

I may just have to post without waiting for Fabri. = 3=