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"
A Frosty Crater On Mars
01/12/2000
In the martian southern hemisphere, autumn has arrived. As on planet Earth, the cooler temperatures bring a seasonal frost to the landscape. Of course on Mars, the surface temperatures can be really cool, reaching below minus 100 degrees C. This detailed Mars Global Surveyor synthesized color image of Lowell crater at 52 degrees south martian latitude was recorded on October 17. Whitish frost has begun to accumulate on floor of the 201 kilometer wide crater. The crater's weathered walls suggest Lowell is relatively old. In striking contrast, two smaller, sharp-rimmed young craters are clearly superimposed on the older features near Lowell's outer rim.