Sandstone hoodoos in an eroded landscape. Hoodoos are spires of eroded sedimentary rock with a piece of harder rock on top, which protects the stone from the elements. They normally form in arid basins and badlands (arid terrain rich in clay soil), which can be easily eroded by wind and rain. Photographed in the sacred Blackfeet tribal area of Writing-On-Stone Provincial Park, Alberta, Canada.