Phlegra Montes is a range of gently curving mountains and ridges on Mars. Flow patterns attributable to water are widely visible across the image. Linear flow patterns can be seen inside the valley (Box 1). Nearly every mountain is surrounded by an apron of rocky debris (Box 2). Over time, this debris appears to have moved down the mountainside and looks similar to the debris found covering glaciers here on Earth. Lobe-shaped structures seen inside impact craters in the region (Box 3) are known as concentric crater fill and are perhaps another indication of subsurface water ice. The High-Resolution Stereo Camera on ESA’s Mars Express collected the data for these images on 1 June 2011 during orbit 9465.