S1, E3: Zeinab Badawi explores what is in store for opera as it embraces greater diversity and innovations. She talks to two established leading lights, Italian mezzo Cecilia Bartoli and Peruvian-born tenor Juan Diego Florez, and two rising opera stars who are fast establishing their careers as names of the future, South African soprano Masabane Cecilia Rangwanasha and French tenor Benjamin Bernheim.