This is a picture of the ice cap at the South Pole on Mars. This picture was shot from Mars orbit in 2000 by a spacecraft called Mars Global Surveyor. The white regions are ice. Most of the ice is water ice, but there is also a thinner layer of dry ice (frozen carbon dioxide) on top of the water ice. The ice cap is about 420 km (260 miles) across. It was summer in the southern part of Mars when this picture was taken. In the winter, the area shown in this picture is completely covered by dry ice.
Image courtesy of NASA/JPL/Malin Space Science Systems.