The Biosphere, located in Arizona, South of Phoenix.  This is the place scientists live inside of, to determine if a true artificial atmosphere can be made to sustain life.  Results of such experiments could be useful if long periods of travel in space or on other planets is ever realized.

This is the Main Entrance to the Biosphere.

"Centurions" standing guard located outside of the Biosphere.  The place is full of these metal sculptures.