The surface of Mars is not a terribly friendly place. Our information about what life is like on the surface of the red planet comes from numerous Mars landers which have taken geological samples and other data, along with data from the Mars rover landings and various orbiting spacecraft. A great deal of useful data has been collected using these techniques, and humans know more about the surface of Mars than they do about any other planet.
As people who have seen images taken by spacecraft on Mars may have noted, the Martian landscape is similar to that of a desert. Most of the surface of the planet appears to be made from basalt, and the surface is covered in a layer of iron oxide dust. This red dust is what gives the planet its distinctive appearance. In the Southern hemisphere, the planet is heavily pitted with craters, while the Northern hemisphere has more shield volcanoes and evidence of recent geological activity.
The atmosphere of Mars is every thin, and the planet is a cold, windy place. High winds create tremendous dust storms which can cloud the atmosphere for days. In the summer, the surface of Mars can reach a high of 68 degrees Fahrenheit (20 degrees Celsius), and in the winter, it gets down to a chilly -220 degrees Fahrenheit (-140 Celsius). The planet cannot insulate and trap heat very well, and the atmospheric pressure is low, making it difficult for water to exist in a liquid form on the planet's surface.
To the north, the planet has an ice cap which consists primarily of carbon dioxide ice and some trapped water. Mars also appears to have significant ice deposits beneath its surface. At one time, this water may have been in liquid form on the surface of the planet. Mars has around 38% of the gravity of Earth, which would make Martian basketball a rather exciting sport.
There are two notable geological features on the surface of Mars: a huge shield volcano known as Olympus Mons, and a deep valley called the Valles Marineris. The thick crust of Mars is also marked by a number of channels and grooves which suggest that liquid water once existed. According to data sent back from Mars exploration missions, the planet experiences little to no geological activity, and is essentially in a state of stasis. However, life forms did once exist on the planet, as evidenced by traces of their presence in geological samples, and some scientists have theorized that simple bacteria and other organisms may still be present, perhaps in the icy regions under the surface of Mars.