Inca_City
During the Mariner 9 mission in 1972, when first closely mapping features on Mars, members of the imaging team noticed a very strange feature at 82° S latitude and 66° W longitude. A straight grid of straight walls and square depressions, typically 3 km on a side. It was a natural formation, but the origin was difficult to determine. Mariner 9 teammates informally referred to this formation as Inca City, just as Viking teammates later quirkyly affectionately dubbed it Face on Mars . It vaguely resembles the ruins of an ancient abandoned city with walls and squares. If you wanted to pretend there were alien artifacts on a distant world, Inca City might have been a better candidate than Face on Mars. Book: A traveler's guide to mars