The 6,500 windows over Biosphere 2's 3.14-acre laboratory get their first cleaning in 7 years. It's the biggest window-washing job in the world. Window washers will complete the Herculean task of cleaning all 6,500 windows that enclose the Biosphere 2's 3.14-acre living laboratory the week of Oct. 27. A crew of six window washers from the 5 Star Window Care company of Phoenix have been working from sun up to sun down for more than a week to clean the windows, which haven't been washed in seven years, said John Adams, assistant director of planning and facilities at The University of Arizona's Biosphere 2. Once cloudy, opaque glass in the 91-foot tall, 7.2-million-cubic-foot steel-and-glass space frame structure now sparkles, both enhancing the appearance of the stunning dome and increasing the amount of sunlight that 3,000 species of plants inside need for photosynthesis. Windows over the rainforest, savanna, wilderness and ocean biomes now shine. Windows over the desert biome are the last to be washed. Washing is a 3-step process. The crew first uses a special detergent and water-feed poles that look something like long car-wash brushes to break through years of biological and mineral build-up. The next step is pressurized-water rinsing using water filtered by reverse osmosis to prevent water spots. The final step is power rinsing using deionized water. Adams originally estimated that the window-washing job would take more than three weeks, but the crew is finishing in about two.