Between 2012-2015, excavations in Area F uncovered a monumental building complex organized on three artificial terraces that regularized the slope of the volcanic terrain. It measures approximately 60x35 m, occupying an entire city block. It is prominently situated at one of the most central locations within the city, on the main urban thoroughfare at the important intersection of the roads from Tibur, Praeneste, and Rome. Stratigraphic evidence and construction techniques date the original phase (Phase 1) of the building to the mid-third century BCE. The preliminary interpretation of this complex is as a public building, with spaces designed for a variety of functions – bathing, public feasting, ritual activity, and possibly administration. It represents one of the very few examples of public buildings other than temples and fortifications known from the mid-Republican period, and sheds important light on the development of Roman architecture and of the Latin cities in a crucial and obscure period.
Subsequently, beginning in the mid-first century BCE as the occupied area of the city of Gabii as a whole contracted, the complex went through a succession of reconfigurations (Phases 2-4), with the middle and upper terraces being completely abandoned and backfilled by the early imperial period. The lower terrace was repurposed to accommodate a series of small shops and latrines, which remained in use at least into the fourth century CE.