This picture shows strange patterns on the surface of Mars near the planet's South Pole. Similar patterns are found in the Arctic and Antarctic on Earth. Patterns like these have also been spotted near the North Pole of Mars. On Earth, polygon patterns like these usually form when ice under the ground freezes and thaws over and over again. Polygons on Mars might form in a similar way. If they do, there might be water ice beneath places where the polygons are found.
Spacecraft in orbit around Mars have taken pictures of many other odd, and often beautiful, features and patterns. Many of these are on land near the poles of Mars and on the Martian polar ice caps. As the seasons change on Mars, dry ice (frozen carbon dioxide) in the polar caps freezes and sublimates. This cycle of changes creates weird fingerprint terrain, many pits, swiss-cheese terrain, and strange spider web patterns. The North Pole of Mars is surrounded by a huge field of sand dunes. Dunes near both poles have odd patterns each Martian year as they lose their winter ice. Layers of ice and dust, laid down year after year, have built up layered terrain near both poles.