This eco-community concept would be intended for use in some rather harsh environments that might be chosen for their economy or to really put notions and technologies of self-sufficiency to the ultimate test and would serve as a direct analogy to subterranean settlements likely employed on future lunar and planetary settlements. Relying on either a natural strata suitable for simple excavation by roadheader, employing a system of reinforced concrete shells in less stable strata, or even using a ‘built-up’ structure combining concrete shells with earth berming, Terra Firma would be a largely below-ground community complex employing a network of excavated and open (but optionally skylight-topped) avenues or ‘canals’ and circular or oval atriums linked by short tunnels. Individual residences