This image shows large sand dunes in the North Polar sand sea on Mars. It is one of a series of repeat images of the same dunes, taken at different times, in order to determine the type and extent of changes in the dunes over time.
Dunes tend to migrate slowly on Earth under continuous wind regimes (on the order of several to tens of meters per year), and we are just starting to verify movement on Martian dunes with these repeat HiRISE images.
I guess it enables me to always see the world around me as though it was for the first time. It is always fresh with new things to see everywhere. I think as we grow older we tend to notice less and less of the world around us, it all becomes familiar and unsurprising. Photography prevents this and lets me see the world as a child does with wide eyes and a sense of wonder.