A Streamlined Form in Lethe Vallis, Mars

This image shows a portion of Lethe Vallis, an outflow channel that also transported lava. This is one of only a few places on Mars where these pristine-appearing landforms have been identified. The channel formed by catastrophic floods, during which it produced the prominent crater-cored, teardrop-shaped island in the middle. via NASA http://ift.tt/2c6qZ6U