Located on the top floor of Smithonian Natural History Museum this was a great venue since everything else on display does not move. Suggest getting tickets on line just to save you time. Tickets purchased online can be picked up at the Johnson Imax booth or at the ticket booth outside the butterfly pavilion. The room is not big but is full of plants, butterflies and cacoons.
Dispite the bright lights in the room and the number of people the temperature seems, to me, to be comfortable. Once your are allowed in the room you are not rushed. This might cause some patience issues with those waiting to get in since only a certain number are allowed in at one time. If you don't want to go into the pavilion there is a window, on the side of the pavilion, that enables you to view what is happening inside.