Mars is unique from any other planet in the solar system in that it possesses all the raw materials required to support a new branch of human civilization. Many prominent scientist's of the present day feel that the only alternative location for a human civilization would be the Moon; however, Mars is without a doubt the better site for a human civilization of the two.
In contrast to the Moon, Mars is abundant with carbon,
nitrogen, hydrogen, and oxygen. The Moon, on the other hand, contains these
elements in a rather insignificant amount, usually in parts per million quantities.
The Moon is also deficient in about half the metals of interest to industrial society;
such as, aluminum, silicon, and copper, as well as other elements like sulfur and
phosphorus. Obviously, concerning resources, Mars has a huge advantage over the
Moon. In fact, the geologic history of Mars has been compared to that of Africa,
concerning its minerals and volcanic action.
Concerning power supply, power can be generated on either the Moon or Mars with the use of solar panels, and here the Moon's clear skies and closer proximity to the Sun have the advantage over Mars. Mars however holds an enormous advantage over Moon in manufacturing solar panels, so as to create a self-expanding power base. This advantage is obviously held due to the resource edge Mars holds. In addition, Mars has the potential for wind generated power while the Moon clearly does not. But both solar and wind power offer relatively modest potential as opposed to geothermal power. Mars, as previously discussed, has the potential to be a strong geothermic power-based site. The Moon, on the other hand, lacks this potential because sunlight is not available in a form useful for growing crops.
The Martian atmosphere is extremely thick as opposed to the Moon's atmosphere which is very thin and composed of sparsely spread out molecules. Therefore, the thickness of the Martian atmosphere will work to protect from solar flares. In addition, the greenhouses on Mars, which are protected by unpressurized UV-resistant hard plastic shield domes, can be used to rapidly create crop land on the surface. Greenhouse's on the Moon, on the other hand, would create almost unbearable temperatures, whereas, on Mars, the temperature would yield an extemely climatic atmosphere.
The point to be made is that Mars is the ideal place for further continuing human colonization. Mars is a place where humans can live and multiply to large numbers, supporting themselves with products over every description made out of indigenous materials. Mars is thus a place where an actual civilization, not just a mining or scientific outpost can be developed. And most significantly for interplanetary commerce, Mars and Earth are the only two locations in the solar system where humans will be able to grow crop for export.