Curiosity on Mars photographed this strange tower February 13, 2013.
Top photo information: Above I indicated in red and surrounded the strange shaped stone hollow tower.
Above I enlarged the strange TOR.
The photo that interests us was taken by the robot on the ground on Mars "Curiosity" February 13, 2013, and posted on the official website by 14 February 2013. The coordinates of the photo are: MASTCAM RIGHT SOL 186.
THE PHOTO IS HERE: