Opportunity Rover Finds Strong Evidence Meridiani Planum Was Wet Scientists have concluded the part of Mars that NASA's Opportunity rover is exploring was soaking wet in the past.
http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040302a.html
"Liquid water once flowed through these rocks. It changed their texture, and it changed their chemistry,"
All Info and pics and graphs can be found here: http://marsrovers.jpl.nasa.gov/home/index.html