Opportunity lander (centre) in Eagle crater on Mars. The tracks made by the rover Opportunity are seen criss-crossing the crater floor around the lander. Opportunity landed in Eagle crater on 24th January 2004. It spent around two months studying rocks and soil in the crater for signs of water. It then headed to a larger crater, called Endurance, over 600 metres away. Opportunity, and its twin rover Spirit, found much evidence that water was present on Mars in the distant past. The finding raised hopes that life might once have existed there. Image taken on 22nd March 2004.