Mars
Mars is the fourth planet from the Sun and the seventh largest in the Solar System. A cold, dusty desert world with a thin atmosphere (mostly CO₂), the planet features extinct volcanoes, deep canyons, polar ice caps, and seasons. Mars has two small moons (Phobos and Deimos), a day just over 24 hours long, and a year lasting about 687 Earth days. It is a prime focus of robotic exploration and studies about past water and habitability.
Source: science.nasa.gov
APODs including "Mars"
Half Dome Rock on Mars
30/09/1997
Who ordered the Martian pizza? As Mars Pathfinder and its mobile robot Sojourner continue to explore Mars, new and interesting rocks are being discovered, even though the primary mission has been successfully completed. The rock pictured above has been dubbed "Half Dome" and was visited by Sojourner in late August. The shape and fine-scale textures of Half Dome are still being studied. As part of the extended mission, Sojourner has been sent on its longest journey yet - a 50 meter stroll around the Sagan Memorial Station.