Earth or Mars?

Sedimentary Rocks in Valles Marineris, Mars

Is this picture of Earth or Mars? It sure looks a lot like some places on Earth. It is actually some exposed bedrock in the canyon named "Valles Marineris" on Mars. You can follow this link to the original picture and more pictures of: Martian sedimentary rocks.

A lot of these sedimentary rocks have all the characteristics of water laid sediments. The evidence for abundant water on Mars at some point or points in its history is pretty overwhelming. The big question is; where did all the water go? How long ago and is there any left are two other big questions. I don't have any reason to believe this, but I just have a feeling that the water was there, not so very long ago. That most of it disappeared billions of year ago, just does not seem reasonable somehow.