The surface of Mars is approximately equal to the land surface of Earth. It’s big.

http://www.msl-chemcam.com/index.php?menu=inc&page_consult=t... - Mars 101#.UvuUrHbfMdc

We have there only ¿three? moving robots there, but IIRC one is not moving and one is not working. And there are some (maybe 10) full static platforms, but I don’t know if any of them is working now.