More than 40 years after her death, the extraordinary voice of Maria Callas, "La Divina Assoluta," still remains unsurpassed. It has the power to divide critics, some finding it monstrous, others transcendent. Artists like Patti Smith, Linda Ronstadt and Nina Simone have cited Callas as a major influence and inspiration. She remains one of the most important female voices of the 20th century.