They say you can't judge a book by its cover but, with planets, first impressions do count. New images show where complex fault lines in Mars' Phoenicis Lacus region have resulted in terrain with a distinctly contrasting appearance. Nineteenth-century astronomers were the first to see Phoenicis Lacus on Mars. They identified it as a dark spot, and thought that it resembled a sea. Now we know that it is not a body of water but the southwestern extension of the complex Noctis Labyrinthus system, which stretches away from the giant volcanoes of Mars's Tharsis region.