The Sandberg, a hill ridge in the northwestern part of the Weinviertel region of Lower Austria approximately 70 km north of Vienna, is one of the potentially most important archeological sites of the middle La Tène culture in Central Europe. The settlement which flourished there was not fortified, and therefore does not qualify as an oppidum. However, what is known to date suggests that it was not only large (probably covering more than 400,000 square metres) but also a wealthy and powerful center for trade, culture, religion and political power between southern Bohemia and the Danube valley. Its inhabitants are likely to have been Boii, or belonged to a Celtic tribe that was under their direct influence. Location The Sandberg ridge (situated at ) separates the villages of Platt and Roseldorf in the district of Hollabrunn. It consists almost entirely of fertile Löß soil and has been subject to intense agricultural use for centuries. Its summit, although not high, offers a panoramic view far into the surrounding countryside, suggesting strategic considerations might have played a significant role in the selection of the location. While the inhabited area (as far as it has been delineated by surveys) was situated on the southern slope of the hill on the territory of Roseldorf, Platt has much better logistic connections and traditionally harbors the archeologists' base camp. Identification and primary characterization Although surface finds of Celtic coins (about 1,200 have found their way into the numismatics collection of the National Museum of Arts in Vienna) and other artifacts had been reported since the late 19th century, the true importance of the site began to be appreciated only by the 1990s. It was not before 1991 that the area was placed under legal protection as a cultural heritage site. From 1995 to 2000, geomagnetic surveys were carried out which covered 220,000 square metres and identified 450 distinct subterranean structures consistent with the remains of wooden houses, an enclosure in the south, and a cluster of three larger quadratic structures. Results from pilot prospections beyond this characterized area, as well as the history of surface finds and accounts from the local population, suggests that the settlement could have been at least twice as large. Excavations Systematic excavations commenced in 2001, and initially probed only a very small (18 x 25 m) segment of what had been interpreted as a residential zone. The sunken foundations of three