The New Mexico desert is a landscape of harsh extremes: brutally hot in the summer, frigid in the winter. It was the perfect testing ground for architect Mike Reynolds' "earthships"—houses of unconventional design material and utility that are completely self-sustained. They're built with used tires and empty glass bottles and produce their own electricity, water and food. For Reynolds, sustainable houses are the key to making a home in a better future—and now, the rest of the world is catching on to Reynolds' eco-friendly designs.