Today's Image of Mars shows ancient hills in Phlegra Dorsa surrounded, and sometimes overwhelmed by flows that came out of Cerberus Fossae. The flows were made up of mud or lava flows, and maybe a combination of both.
Flow after flow came out of the fracture in Mars called Cerberus Fossae, each one building on the previous, until eventually some of the flows got high enough that they covered portions of the ancient hills. Should we send a rover down to the area surrounding these hills we could gain valuable insight about the contents of these flows and the time during which they were released from Cerberus Fossae. If we understand these two things we might be able to determine what triggered the cataclysmic releases, which could help us to understand if something similar could happen on present-day Mars.
Clicking on this image will take you to the original high resolution image from HiRISE. [See their caption for the image]