Paolo Soleri, the futuristic, eco-conscious architect, died yesterday at 93.

Arcosanti Apse:  Wikimedia Commons

He is best known among the masses (and in the scientific community, to some extent) for his planned city of Arcosanti, a sort of Xanadu for the eco-conscious set. When it broke ground in 1970, Soleri saw the proposed 5,000-person city-complex north of Phoenix as a place where cars would be unnecessary and resources used only minimally. It's compact and, since it's elevated about 3,700 feet, it's literally a city on a hill. The buildings share the mostly brown palette of the surrounding desert, but a panoramic view shows a skyline full of unexpectedly lovely geometric shapes.