What made Maria Callas the world's 'greatest diva' Houston Rogers/Victoria and Albert Museum Maria Callas as Violette in La Traviata It's 100 years since the birth of the opera singer Maria Callas. Callas is featured in a major group exhibition, Diva, at London's V&A Museum until April 2024; the show reframes the "diva" concept, from 19th-Century opera stars to contemporary …