Mars has similarities to Earth in its composition and orbital properties. A Martian day - 'sol' is extremely similar to an earth day. Its rotation period and axis of obliquity is similar to that of Earth. Therefore Martian seasons are Earth-like. Conclusive proof of presence of water in form of polar ice caps came from the Pathfinder data.
Martian terrain has flow channels similar to terrestrial dried riverbeds.
These channels widen as they flow downwards, a property shown by flowing water. The Martian meteorite ALH 84001 showing fossils of some microbial life have rekindled a lot of interest in this planet. Mars Surveyor 2001 mission has been undertaken by NASA as one step ahead in its long term plan for Mars exploration. This mission has two parts - Lander and Orbiter. Try making rocket fuel on Mars for future return trip missions from Mars.