Mission to colonise Mars

In the race to expand mankind's presence in space, the non-profit Mars One mission hopes to be the first in putting human boots on Martian ground by 2025. This year the Netherlands-based group will choose 24 finalists for the one-way, $6-billion mission to start a Martian colony, with plans to capture the experience in a reality TV show. What do humans stand to gain from colonising Mars?