What is a human being's natural habitat?

It's kind of a conundrum to me.

With what we are able to do with our minds, and the technology that has come from them, we've made almost every part of the surface of this planet livable to some extent. There are stations in Antarctica that are manned year round and that have had some scientists living in them for well over 2 years at a time. We have submarines and under water stations that can be manned in a similar way. I would also suspect it's possible to live on mountaintops with our current capabilities. All of these are only a matter of trucking the right resources to the right spot for resupply or taking the spot to the supplies as the case may be.

Viability of a habitat at this point is only limited by the effort and expense that can go into starting it and what can be allowed to keep it going, I guess. So, it may be that our natural habitat is only an area into which it's viable to keep the resources of survival flowing if those resources can't be found in the area naturally. Of course that may fluctuate over time and through different circumstances in all areas.