Every time I see people get excited about Martian human habitation, I note a lack of discussion of the essential intermediate step: a fully self-sustaining base in the most inhospitable parts of Earth.
Where are the Biosphere++ projects?
And Amundsen-Scott has it easy: pressure, oxygen levels, and dust aren't a problem! (granted: Martian equator has easier temperatures).
Also, I've long wondered what is the comparable level of yearly insolation (for sustainable power) in the South Pole compares to Mars' equator?