Phoenicis Lacus was formed by the uplift of the Tharsis volcanic plateau. The continual episodes of strong volcanic activity in Tharsis not only lifted the plateau, but also deformed Phoenicis Lacus, creating uplifted blocks and multiple fault lines at different orientations. A prominent collapse feature in Phoenicis Lacus sinks to a depth of about 3 km below the surrounding terrain. This image was created using a Digital Terrain Model (DTM) obtained from the High-Resolution Stereo Camera on ESA’s Mars Express spacecraft. Elevation data from the DTM are colour-coded: purple indicates the lowest-lying regions, and grey the highest elevations. The scale is in metres.