NASA says its Mars Odyssey spacecraft has spotted seven possible cave entrances on Mars. These dark features, several hundred feet across, have a more constant temperature from day to night than the ground surrounding them (as shown in the infrared images at center and right). If the "Seven Sisters" holes turn out to be caves, it's possible they could provide a protected niche for past or present life on Mars—or serve as underground shelters for future human colonization.—Dawn Stover
It's amazing how one unique discovery can possibly bring us closer to the past and the future simultaneously!
With the fear of wind, radiation and meteors, the cave would appear to be the perferred place to set up shop -
I can't recall any cave being destroyed by a tornado or hole in the roof caused by a meteor - also constant temperature would reduce heating and cooling requirements -
Australians have built underground developments. Humm!!