The Conserva di Valverde, better known as the Bagni di Mario, is a cistern built in 1563 in the heart of the Bolognese hill. Its "nickname" is due to the erroneous thought, given its even more ancient and surreal aspect, that they were ancient spas dating back to the republican period under Caius Mario. It is a limestone dome in which to descend to over thirty meters deep, in an incredible environment of tunnels, excavations, corridors and wells. Where a limestone waterfall breaks in the middle of a dark tunnel where it seems to be lost. This cistern collected the water useful to feed the Fountain of Neptune, the symbol of Bologna and during the bombing periods it was a refuge for the Bolognese, as shown by the different signs between the various corridors. This is one of the places we loved most for this project, one of the first visited, the one where I"Succede solo a Bologna" has allowed us to work better. An incredible cold while a torrid summer was taking place outside. An enveloping darkness and fog, of humidity, which helped to create the right environment. A curiosity should be asked to our model who, dressed in a tunic, suffered from the cold while the rest of us seemed ready for an arctic expedition.