Sed omnium operum magnitudinem circumveniunt cavernae, ingentem in altitudinem pressae ad accipiendum impetum fluminis: quod ubi appositae crepidinis fastigium excessit, urbis tecta corriperet, nisi essent specus lacusque qui exciperent.
Moreover, all of these magnificent constructions are encompassed by man-made depressions, excavated to a tremendous depth in order to meet the surging waters of the river. In the event that the river rises above the peak of the barrier established to contain it, it would wreak havoc upon the structures of the metropolis, were it not for the presence of the depressions and reservoirs to apprehend it.