"December 4, 2000 -- In what ultimately may be their most significant discovery yet, Mars scientists say high-resolution pictures showing layers of sedimentary rock paint a portrait of ancient Mars that long ago may have featured numerous lakes and shallow seas." This exciting news comes from a recent NASA news article detailing the latest finds from the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft. Nice, clear images of terraces possibly consisting of sedimentary rock layers accompany the text.