Isturitz, Oxocelhaya and Erberua Caves are located in the foothills of the western Pyrenees. The landscape is hilly and is crossed by a wide valley with a small river, the Arberoue. Downstream, the river disappears into the limestone of Gaztelu Hill: this underground flow created the Erberua Cave. Above this natural tunnel we observe three fossil staged caves: Oxocelhaya, Isturitz and Rocafort. The Gaztelu Caves provide a major European Prehistoric archaeological site. The first recorded data came from the Isturitz Cave (1895), then from the Oxocelhaya Cave (1929) and finally from the Erberua Cave (1973) giving evidence of human occupation during the Mid-Upper Palaeolithic period. These archaeological remains are not uniformly distributed. In Erberua, some of the paintings suggest a Gravettian use of the cave but the works date from the Magdalenian time (Middle and/or Upper). In Oxocelhaya Cave, the settlement may date from Aurignacian time but the art works generally date from the Magdalenian time. In Isturitz Cave, the importance and diversity of the Aurignacian objects are exceptional and prove the permanent nature of this settlement where numerous activities took place. Also during the Gravettian time, an enormous quantity of material is proof of a very important human presence. During the Middle Magdalenian time, the activities are marked in particular by hundreds of portable art, this is why this cave has been described as one of the most important aggregation sites of the Pyrenees. The research team is multidisciplinary and was established in 2011 around twelve main objectives. Our contribution concerns the first two stages and includes speleologists, geologists and karstologists. The first stage was the charting of the numerous listed activities and the second stage will analyze their organization according to the topographic, geological and karstologic specificities of the Gaztelu Hill.