Ashlar pillar that delineated the Via Gabina and separated it from the area F complex. It's similar in nature to the other pillars along the road (5721, 5722, 5723, 5724, 5725, 5727, 5728). An adjacent rectangular tufo block appears to be the result of a collapse from this SU.
Tufo pillar W of 5728 along Via Gabina