In Ares Vallis, teardrop mesas extend like pennants behind impact craters, where the raised rocky rims diverted the floods and protected the ground from erosion. Scientists estimate the floods had peak volumes many times the flow of today's Mississippi River.
This image was taken by the Thermal Emission Imaging System instrument on NASA's Mars Odyssey orbiter and posted in a special December 2010 set marking the occasion of Odyssey becoming the longest-working Mars spacecraft in history. The pictured location on Mars is 15.9 degrees North latitude, 330 degrees East longitude.
Photo credit: NASA/JPL-Caltech/ASU