The Lapidarium is an open-air archaeological exhibition of epigraphic monuments from the Roman era. A number of 56 monuments discovered in the old Roman settlement of Montanesium (present-day Montana) are located in the middle of the park in Popska Garden. The marble inscriptions represent extremely valuable testimonies for the culture and history of this region from the 2nd-3rd centuries AD. They are the only written sources for this provincial Roman city and provide information about the ancient cult for the goddess Diana, who was the protective goddess of Montana, the god Apollo, Esculap, Hygiea, Latona, Silvan and other deities, but also important historical data about the visitors here, as well as the military units stationed in this garrison. The inscriptions carved in stone and marble also speak of the glory of the Roman emperors, of the rulers and governors of the province of Lower Mizia, as well as of the fighting facts of some military and civilians.