For the first time, the Catholic Church is allowing scientific experts and historians to openly test the veracity of the remains of reported saints. National Geographic has exclusive access to the forensic investigation. Deep in the crypt below the Cathedral of Reggio Emilia lie a set of bones believed to be those of two ancient saints, Chrysanthus and Daria. For more than 1,500 years they've been hidden away... until now. Can science prove that these are a man and woman who were brutally executed by the Romans in the fight against a growing Christian faith?