Architect Matthew Fromboluti designed this inverted skyscraper to make use of abandoned open-pit mining operations in Bisbee, Ariz. The 900-foot underground building (maybe we should call it a mantle-scraper?) wouldn't just be for residences — it would comprise an entire self-sufficient subterranean city, including crops fed by skylights. 

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This isn't just an attractive way to heal a 900-foot-deep, 300-acre mining scar. It could also be the most energy-efficient way to live in the desert. The underground city would be shielded from sunlight, and the structure is shaped to vent hot air, so it's naturally climate-controlled. And while light rail would connect the Üntertown to nearby Bisbee, the in-house farm would mean residents wouldn't need to truck in food supplies.

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