As you leave Cafayate on Route 68, which goes to Salta, don't miss the astonishing site of Los Medanos on your right (only in dry weather): a long series of dunes of immaculate sand, a result of the erosion of limestone deposits and containing mica particles that make it stand out in the sun. The wind constantly sculpts the contours of the dunes into endless little waves. A striking show and a very entertaining walk (but hard work on the calf muscles!).