This image represents one of many monitoring sites at the South pole residual cap (SPRC). Images are taken throughout the Martian year to document changes in carbon dioxide ice coverage.

This image shows a popular spot where one of the features resembles a smiley face that is approximately 500 meters across. If you smile at Mars, sometimes it smiles back.

Written by: Livio Tornabene, Ryan Hopkins, Kayle Hansen, Eric Pilles (audio: Tre Gibbs)   (7 January 2015)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_039115_0945

Image: NASA/JPL/University of Arizona