The strange smiley face turned out to be the tip of a small toy commonly used by kids - a mini stamper. 'Do you have any kids?' the user who cracked the case asked the father. 'This looks like the ...

A ‘smiley ... the face, the ESA said: ‘Once a world of rivers, lakes, and possibly oceans, Mars now reveals its secrets through chloride salt deposits found by our ExoMars Trace Gas Orbiter.