The bizarrely beautiful Pierres Bleues are the work of Belgian artist Jean Verame, who spray-painted the smooth, rounded boulders in shades of blue, red, purple and black in 1984. Decades later, they remain vivid against the red desert. Visitors disagree over whether it's art or a blight on the landscape, but villagers give the rocks a fresh coat of paint every year to keep the controversy fresh.
You'll find them some 7km south of Tafraoute, 500m past the turnoff for Aït Mansour; a piste leads uphill to the right.
