Mars, on the other hand, has an atmosphere of sufficient density to protect crops grown on the surface against solar flares. On Mars, even during the base building phase, large inflatable greenhouses made of transparent plastic protected by thin hard-plastic ultra-violet and abrasion resistant geodesic domes could be readily deployed, rapidly creating large domains for crop growth.
http://www.nw.net/mars/docs/m_econom.doc
Remaining habitats, not inside big plastic domes, would be located underground in a subterrenean setting.
Cheers!
]]>