Take a look at this… A repeat pattern of dune-like areas form on Mars. NASA scientist call these fluvial dunes – formed by the flow of water. They’re identified by a prominent crater-core, with a teardrop-shaped island in its middle. These pictures were taken by a NASA Mars orbiter in May of this year. Scientists say the landforms were created by massive and catastrophic floods. The dune’s channels also likely allowed lava to flow on Mars.