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"
Water-Ice Imaged in Martian Polar Cap
19/02/2002
Does water exist today on Mars? Yes, although the only place on Mars known to have water is the North Polar Cap, and that water is frozen. Views of this potentially life-enabling water-ice are usually obscured -- in the winter by darkness and in the summer by clouds. Last April, however, the orbiting Mars Global Surveyor spacecraft was able to get a good glimpse of the water-bearing cap just before Martian spring. Low, dark layers in the above image are thought to contain a large amount of sand, while high, light layers likely contain higher amounts of water-ice. The image spans an area about 5 kilometers across.