In the mid-thirties Nervi worked for the Navy a prototype project for an underground oil tank. Were developed different solutions of the project and made some specimens in Cagliari, in Gaeta, in Palermo, in Sircusa, in Taranto and in Pozzuoli near Naples. The research started in 2013 on the works achieved or planned by P. L. Nervi in Campania allowed the recovery of important archival documents, from which it is able to reconstruct the innovative system designed by the great architect and builder of the twentieth century, and to initiate a field survey for check the current condition of the tanks still exist in order to promote the proper conservation and enhancement.