Opera Ipogea has been the scientific journal of the National Commission for Artificial Cavities of the Italian Speleological Society ETS since 1999. In almost 25 years of activity (two series, fifty issues, several monographic works and special issues), more than 520 contributions have been published in Opera Ipogea, documenting thousands of man-made works underground throughout the ages. The journal, today with the extended title Journal of Speleology in Artificial Cavities, disseminates the results of the most important study campaigns conducted in artificial cavities around the world; moreover, hosts the proceedings of national and international conferences, round tables, workshops and thematic censuses of artificial underground structures, accrediting itself as the most important international journal in the field. Its scientific committee includes leading national and international experts who, among speleologists, historians, archaeologists, architects, engineers and geologists, boast diverse and long-standing experience in all aspects of human activities in the underground.