Here is a perfect example of recent water activity on Mars. The color image shows the area, the anaglyph shows it in 3D. The small “tide pool” to the right is a new formation. How do we know? Because we see how rapid the erosion on Mars is by comparing day-to-day pictures. This formation is made by a liquid (wonder which one?) and had to be formed within a few days to possibly a couple of weeks. Wind cannot make this formation; only the retreat of a liquid. Not waffling here, this is made by water. Opportunity, sol 50.
And here is the 3D view, use your red/blue glasses and see something amazing.