Evidence for Past Life on Mars

The overachieving rovers have done it again. Spirit, while working on a plateau called Home Plate, has discovered a patch of almost pure silica (i.e. glass). The current thinking is that the patch came from hot springs coming up from underground or a fumarole where acidic steam comes. On Earth, these hot springs are always covered in microbial life.

Not conclusive but all the evidence seem to point toward life.