Sputnik Planum

Explanation: This annotated view of a portion of Pluto's Sputnik Planum (Sputnik Plain), named for Earth's first artificial satellite, shows an array of enigmatic features. The surface appears to be divided into irregularly shaped segments that are ringed by narrow troughs, some of which contain darker materials. Features that appear to be groups of mounds and fields of small pits are also visible.

Pluto

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.