Today's Mars Photo was recently taken by Mars Reconnaissance Orbiter's HiRISE camera. The image shows an impact crater in eastern Elysium Planitia, a relatively flat expanse of land. Lava flows have filled in most of the plains, thus removing evidence of most impact craters in the area. This crater is so remarkable because it is surrounded by the youngest ever large lava flow discovered on Mars, the Athabasca Valles flood lava. Scientists can watch this crater as it becomes completely filled, like thousands before it in Elysium Planitia. The lava flow has created the channel seen here, through which more lava travels as it fills the crater.
This photo is almost the same size as the original image, so instead clicking on it will take you to the brief explanation of the photo found on the HiRISE website.