which are then stored at the site's research center. Archeological prospecting on Mont Beuvray The prospecting technique used by Bulliot was rudimentary. It consisted of observing the irregularities in the landscape, since the mountain was practically unchanged since the period under study. This allowed him to recreate a plan of the battlements with nearly no excavation. He used this technique to make a scale plan with the help of the army topographers, who made a series of topographical recreations of the landscape. Only the recreation of the Porrey neighborhood exists to this day. In recent years, the same technique has been used in the same Porrey neighborhood with more precise tools, like theodolites and GPS. In fact, aerial and electromagnetic prospecting is made impossible by the vegetation that reforested the mountain since the end of grazing and the excavations of Joseph Déchelette and the nature of the subsoil. One costly but faster technique, tested in 2007, is LIDAR, the use of airborne laser scanners, which are unhindered by the vegetation and can recreate in minutes what usually takes weeks to do on the ground. This will be done in order to attempt to make a complete map of the city and to archive the topography of the location. Organization The research done by Bulliot and Déchelette at the end of the 19th century and at the beginning of the 20th century recreated an organization of the site into neighborhoods, with construction mostly following a central road from the Gate of Rebout to the Great Gates. This organization differs from that of oppida like Manching, where there is a regular urban framework; this is explained by the relief of the terrain, as the battlements encircle three summits with some relatively steep slopes. Since 1984, the excavations have seemed to confirm Déchelette's and Bulliot's hypotheses in broad terms, while nevertheless contributing certain nuances. Battlements Bibracte was protected by strong Murus Gallicus style battlements, which excavations have been able to reconstruct. The city had a progression of two different surrounding walls and at least five restorations of the inner surrounding wall, revealed, among other things, by the study of the Rebout gate. Surprisingly, the inner encircling wall was constructed after the outer wall. The city, therefore, shrank in area from 200 to 135 hectares (494 to 334 acres). The first wall (the internal wall on the map below), discovered by Bulliot, is a