A bunch of rock really. There was this private crowdfunding project where they aspired to build a no-return colony on Mars and auditioned people for it. They wanted to make a tv show and raised like 80 grand or something, while NASA estimated such a thing, if doable at all, would cost 10 trillions. Was a ponzi scheme I guess, or the guys were/are really out of there. Still it's remarkable how many people wanted to go. Not realising that after initial delight is gone - they are stuck in a airless desert with nothing much to do.