English: This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows dark wind streaks on a plain east of Olympus Mons in the Tharsis region of Mars. Streaks such as these change from time to time over the course of a martian year, suggesting that they are the result of wind movement of a thin layer of bright dust. In other words, wind is not moving dark material to make the dark streaks, it is removing bright material (thin coatings of dust). This picture is located near 16.3°N, 127.7°W. The image covers an area 3 km (1.9 mi) across and is illuminated by sunlight from the upper left.