Mars is likely to be the first planet that we might decide to terraforum. Problems with Mars is its low atmosphere and cold temperatures. I have seen many strange concepts for terraforuming Mars. Like nuking Mars (not a good idea) to building factories to pump out green house gases. Personally I would like to see genetic manipulations of bacteria--and etc to help but perhaps crash one of Mar's Planetiods into it---wonder if that is a good idea?