I had wanted to visit Biosphere 2 for some time. We had missed it last trip as it closed early for a function. We made it this time and learned a lot. It was initially developed to create a closed environment. There were two missions: one where folks stayed for 2 years and the second only lasted 6 months before being ended. It is now run by the University of Arizona where they use it to create experiments.
The domes seen in the picture are called "lungs" and were used to store air when the facility heated during the day and return the air at night.
The lungs were essentially connected via a long tunnel to the main building and used a huge diaphram.
The living quarters appeared to be quite pleasant. The picture on the left is a dorm office with the circular stairway to the sleeping quarters. Each Biospherian had their own room. The kitchen was well equipped, but the folks had to learn to cook without oil.
If you want to see the full size set of pictures, click here for a gallery.