The excavation museum (Antiquarium) which was opened in 2006 is located in the Ca ‘del Cap, the information point of the Park, and as well the Documentation Center Davide Pace. The Antiquarium hosts a permanent exhibition concerning the results of the archaeological excavations on the Castle Hill and on the neighboring Giroldo Hill carried out in the 90’s of the last century. The exhibition rooms shows a selection of small finds, especially ceramics, which give an insight into the prehistoric settlements of those two hills. The settlements can be dated now from the middle Bronze Age of the 16th century BC until the end of the Iron Age of the 1st century BC.
Systematic studies about the historical and archaeological situation in the Valtellina were done between 1980 and 1985 and suggested the existence of various proto-historic hilltop settlements in the valley. According to the settlement characteristics the sites always appear in a strategic and dominant position, from where the surrounding valley could be observed and controlled. Characteristics that made these sites interesting even for a resettlement in mediaeval period (Caslido di Dazio, Sassolt di Berbenno, Grumello di Montagna in Valtellina, Castello-Calvario di Tresivio, Dosso and Hill of Santa Perpetua in Tirano, the Castle of Boffalora and the hill of Santa Agnese in Sondalo). However, till the 1990’s none of these settlements has been studied by stratigraphic archaeological research projects. The archaeological investigation on the top of the two hills of Grosio started in 1991 with the support of the Consortium for the Park of the Rock Engravings and under the supervision of the State Authority for Archaeological Heritage of Lombardy (Soprintendenza per i Beni Archeologici dkella Lombardia). After a first field survey that indicated already extensive settlements on the Castle Hill (Dosso dei Castelli) and even on the Giroldo Hill, between 1994 and 2000 six more archaeological excavation campaigns were carried out.
In the same years two more projects were implemented on the Rupe Magna, one for restoration work and the other one for a complete mapping and cataloging of the rock engravings. The results were presented in 1995 in a separate scientific publication. The finds documented during those archaeological campaigns are stored in the archive of the State Authority for Archaeological Heritage of Lombardy, but nowadays exposed in the excavation museum (Antiquarium) of the Park. Hence the visitors have the possibility to study the results of the excavations and to link them to the local history of the valley.