Angustus Labyrinthus

Angustus Labyrinthus is a unique region near the south polar cap. The squares formed by intersecting ridges earned the feature the informal name of the Inca City when it was discovered in Mariner 9 images in 1972. The linear ridges are believed to have formed by volcanic and tectonic forces, where magma filled fractures in the subsurface and then erosion revealed the magmatic material.