Ascraeus Mons

This VIS image of the southern flank of Ascraeus Mons shows a small sample of collapse features that are common in the area.

Photo credit: NASA/JPL/Arizona State University

Note: While collapse features may include pit craters, what we see in this photo are primarily collapsed lava tubes; see this post for a more detailed explanation of similar features on Pavonis Mons. What I find interesting is that some of the older lava tubes have been so eroded away (by the wind) that there are only faint traces of what must have been deeper depressions like those seen on the right hand side of the picture.