The surface of this image looks wavy, like that of the sea. These wave shapes are the result of erosion: the removal of material, which has been ongoing for millions, if not billions, of years. This erosion is likely performed by the action of wind and has revealed layered rock that was deposited in this area in the ancient past.
The layers were deposited very regularly one on top of another and the erosion has cut across them—sometimes shallowly, sometimes more deeply—to create these giant undulations. More resistant layers protrude further, making them the visible crests of the waves. [More at link]