heritage Article “Underground Built Heritage”: A Theoretical Approach for the Definition of an International Class Roberta Varriale Institute for Studies on the Mediterranean, National Research Council of Italy (CNR), 80134 Naples, Italy;
[email protected] Abstract: Although nowadays sustainable reuse of underground cultural heritage has become a global trend, as yet Underground Built Heritage (UBH) is not regarded as a distinctive class eligible for protection. After a critical overview of previous attempts at defining underground heritage by associations such as UIS, SSI and UNESCO, this article updates the definition of the new-born class of UBH on the basis of three main criteria: position (by introducing the concept of Geographical Zero Level), manmade character, and cultural relevance, both material and immaterial. Building on the outputs of several projects devoted to this topic and the results of academic expertise in this field, the author proposes a new dedicated methodological approach consisting of a chart for the classification of artefacts as historical UBH and a strategy for their reuse based on a four-level scale: Re-inventing, Re-introducing, Re-interpreting and Re-building. Keywords: underground built heritage; definition; classification; reuse Citation: Varriale, R. “Underground 1. Introduction Built Heritage”: A Theoretical Although today, regeneration of Underground Built Heritage (UBH) for sustainable Approach for the Definition of an reuse is becoming increasingly popular, being the focus of several internationally funded International Class. Heritage 2021, 4, projects, no generally accepted common definition has been proposed so far. The lack of 1092–1118. https://doi.org/10.3390/ such a definition appears even more regrettable when compared with the clearly formulated heritage4030061 definition of a cognate class, namely, Underwater Cultural Heritage (UCH).