 During the 20th century, writers and performers like C J Dennis, Barry Humphries and Paul Hogan both mocked and celebrated Australian cultural stereotypes, while shifting demographics saw a diversification of artistic output, with writers like feminist Germaine Greer challenging traditional cultural norms.Australia's capital cities each support traditional "high culture" institutions in the form of major art galleries, ballet troupes, theaters, symphony orchestras, opera houses and dance companies.Leading Australian performers in these fields have included the opera Dames Nellie Melba and Joan Sutherland, dancers Edouard Borovansky and Sir Robert Helpmann, and choreographer/dancers such as Graeme Murphy and Meryl Tankard.