Keen to test his theory, Pfanz travelled to Hierapolis in 2013. "We weren"t sure what we would find. It could"ve been made up, could"ve been nothing," he laughed. "We certainly weren"t expecting to get an answer so quickly." But get an answer he did, almost immediately. "We saw dozens of dead creatures around the entrance: mice, sparrows, blackbirds, many beetles, wasps and other insects. So, we knew right away that the stories were true."