This video, uploaded to YouTube a few days ago, purports to show an "alien coffin" visible in photos taken by the Mars Curiosity Rover.
My buddy Kjell send this over to me and said "Sure would love to know whats buried in that coffin." This little box sure does look like a modern coffin concrete liner. As well as the stonework on the back part of the hill that looks like stairs or some left over stonework from some old civilizations constructions.