Eden Patera

Eden Patera is a feature located at 33.6°N 348.9°E / 33.6; 348.9 on the planet Mars. In October 2013 it hit the headlines when it was announced it may be a supervolcano rather than an impact crater, according to research from the Planetary Science Institute in Tucson, led by Joseph R. Michalski. The reason they can look similar is that that a volcano's caldera can collapse, creating a crater, but not from an impact. Some of reasons for suspecting that Eden Patera is a collapsed caldera not an impact crater are its irregular shape, an apparent lack of a raised rim or central peak, and lack of impact ejecta.