Strange cluster of 'spiders' spotted in 'Inca City' on Mars (photo)
Mars' Inca City, formally known as Angustus Labyrinthus, exhibits a linear, almost geometric network of ridges like the Inca ruins on Earth. It is part of a circular feature approximately 53 miles (86 km) wide, suggesting it may be an impact crater with ridges formed by lava rising through the fractured Martian crust and eroding over time.