Biosphere 2 - The Amazing Glass House of Arizona!
The average person's knowledge of Biosphere 2 is probably limited to the movie Bio-Dome (1996) with Pauly Shore. I would admit, that on first glance, it looks like the world's biggest bounce house or the best-est futuristic fort to play lazer tag.
Built to be biologically independent from the living spaces of Earth (Biosphere 1), it houses different biomes (contiguous areas with similar climatic conditions): Desert, Marsh, Ocean, Rainforest, Savanna, Thornscrub.
These areas are adjusted and monitored by researchers who measure the results to better understand how life acclimates to the differences in air, land, and water. Long term hopes are that lessons learned can be used to build self-sufficient biomes any where on Earth ( say Antarctica or a barren desert) or even on other worlds.
The structure, built in 1987, has hosted two closed-door experiments (1991-1993 & 1994) and has subsequently been managed by Columbia University (1995-2003) and now the University of Arizona (2005-present).
Tours are given daily where you can trace the footsteps of the bionauts, see their living quarters, the various biomes (not all are maintained) as well as the lung which regulated air pressure in the structure (it was sealed off from outside air). I was fortunate to take the last tour of the day (in spring 2011) - so those pesky humans are not mucking up all the wonderful photos I took.
The structure is the size of a modern shopping mall, so there's much more to see than you'll have time for, including many outdoor exibits, displays which explain the science behind the experiments and the current uses of the facility. Explore!