Guess what this is

Colonizing Mars would be a lot like living in Antarctica's McMurdo Dry Valley which is the most similar place on Earth when compared to conditions on Mars. The pictures we have seen from Mars look like Sahara but in reality temperatures are way under the freezing point. If there was an abundance of water near the surface, it would be like Siberian permafrost terrain (in some places it is with similar ground features).

The most notable exception would be the great difference in atmospheric pressure. On Mars, water cannot stay in liquid form on the ground for long, and settlers must always wear a pressure suit when out in the open. A mere auxiliary oxygen mask would not be enough. Without a suit, a human would lose consciousness in less than twenty seconds and die in a few minutes if not rescued and revived. The body would dehydrate as the humidity in body openings would start boiling, and the lungs would rupture. People must live indoors or in caves underground and build greenhouses that are sheltered from the harsh environment. It's very much doable.

Young man, go Mars!

http://www.amusingplanet.com/2012/06/mcmurdo-dry-valleys-of-antarctica.html