This is one of the unique stone structures on Mars. It is NASA's Curiosity Rover image.
Image Source - http://mars.jpl.nasa.gov/msl-raw-images/msss/01089/mcam/1089ML0048420010500151E01_DXXX.jpg
NASA said: This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1089 (2015-08-30 01:00:25 UTC).
Image Credit: NASA/JPL-Caltech/MSSS