ON THE EDGE of Terra Sirenum, lava flows and rugged terrain intermingle. Volcanic eruptions from Arsia Mons in Tharsis sent lava streams south and west into the cratered highlands of Sirenum. This view looks north over an old impact crater 43 km (27 mi) wide, and has no vertical exaggeration. Click on the image to download a higher-resolution version (500K).

Image credit: NASA/JPL/Arizona State University, R. Luk