Hesperia, UNITED STATES: Iranian-born Architect Nader Khalili poses in a house at the Cal-Earth (The California Institute of Earth Art and Architecture) in Hesperia, California, 14 April 2007. Khalili’s method, developed from his early studies of traditional architecture in his home country, involves filling sandbags with a mixture of cement and adobe (another word for mud), and connecting them with barbed wire for reinforcement. Khalili once operated architectural offices in Tehran and Los Angeles sold out prior to the Iranian revolution to concentrate making earthen structures. From his Cal-Earth Institute in the Mojave Desert, he promotes a technique which he believes could also be used by NASA for constructing bases on Mars or the Moon. AFP PHOTO/Gabriel BOUYS (Photo credit should read GABRIEL BOUYS/AFP/Getty Images)