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"
Opportunity on Mars
27/01/2004
You've just woken up in a small crater on Mars. The surrounding landscape is barren, strange, and alien. You've never been on this world before. You transmit pictures that are instantly rebroadcast all over your home world. You are the eyes for billions of people. You seek adventure. Your mission is to explore this strange new world and search for signs of pre-historic life. You have six wheels, one arm, and X-ray eyes. Surrounding you, pictured above, is iron sand and light-colored protrusions that might be bedrock. You are the Opportunity Rover that landed on Mars just this past weekend.