At every Martian Winter, a Layer of Carbon Dioxide Ice — CO2 or, also , Dry Ice — condenses in the Southern Polar Regions of Mars, forming a so-called "Seasonal Polar Cap" which is less than 1 meter deep. Early in the Spring, the Ice Layer begins to sublimate (---> going directly from a Solid State to a Gaseus State) both from the top and bottom. In time, the Ice Gas Pressure builds up, until a weak spot in the Ice Layer ruptures; then the Gas rushes out and, as it escapes, it also erodes a bit of the Surface.
This Region of the Red Planet is known informally as Inca City, and it has a series of extremely distinctive Ridges. On the Floor between the Ridges there are Radially-Organized Channels, known colloquially as "Spiders" (and more formally known as "Araneiform Surface Features"). The Channels have been carved in the Surface over many years by the escaping pressurized Gas and, at every Spring, they widen just a bit. This was the first image acquired by the NASA - Mars Reconnaissance Orbiter after the Sun rose on Inca City, marking the end to the Polar Night. A few Fans are visible emerging from the Araneiform Surface Feastures.
Mars Local Time: 16:23 (Middle Afternoon)
This picture (which is a NASA - Original Mars Reconnaissance Orbiter b/w and NON Map-Projected frame identified by the serial n. ESP_037626_0985) has been additionally processed, reduced in size to fit the page, contrast enhanced, Gamma corrected, and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Reconnaissance Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.