The "beach" biome inside Biosphere 2.
If you're interested in Biosphere 2, I highly recommend Jane Poynter's book, The Human Experiment. It's a first-person look inside the experiment, and the best resource I've found on the subject. You can buy it from Amazon:
An incredible idea and calculation event that was bungled by self-serving scientists in fighting who thought it more important to write their names in bad concrete and impure air…
A sad loss for mankind and its advancement into space…
I sometime wonder if it would have been better to have positioned ‘Spirit’ and ‘Opportunity’ in the biosphere2; at least they wouldn’t have had the need to publish early…