A study in shades of blue and brown is actually one of the harshest landscapes on Earth. This glimpse of Africa's Sahara Desert, located near where the borders of Mali, Niger, and Algeria converge, is truly a no man's land, a world of sand and rock without roads or settlements. The horizontal lines across the top half of the image are intrusions of igneous rock, where magma poked up to the surface from deep underground. September 9, 2009.