Crater illusion

In astronomical imaging and Earth imaging, the crater illusion, also known as the dome illusion or crater/dome illusion, is an optical illusion which causes impact craters and other depressions to appear raised as domes or mountains. It is believed to be caused by our being accustomed to seeing light from overhead. When some images are taken from orbit, the light from the sun is nearly horizontal. This is the only time shadows are seen. Our brains are tricked into thinking that the interior of the crater is above the surrounding terrain instead of below it.