This is the flat (ish) area of ground found just above the fort. It is believed to have been the parade ground for the Roman soldiers stationed here. It is also thought that the area is man made, and if this is the case, those Romans certainly knew what they were doing, because as flat as it is, the whole area was bone dry.
"So, , , apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us"?
"Built parade grounds that don't flood"