Hellas Planitia, also known as the Hellas Impact Basin, is a huge, roughly circular impact basin located in the southern hemisphere of the planet Mars. It is the second or third largest impact crater and the largest visible impact crater known in the Solar System. The basin floor is about 7,152 m (23,465 ft) deep, 3,000 m (9,800 ft) deeper than the moon's South Pole-Aitken basin, and extends about 2,300 km (1,400 mi) east to west. It is centered at 42°42′S 70°00′E / 42.7°S 70°E / -42.7; 70
Read more about Hellas Planitia: Description, Discovery and Naming, Possible Glaciers