Joan Sutherland, age 23, sings "O hall of song!", better known as "Dich, teure Halle!", in an Australian vocal competition, 1950. Note the fine diction (in the moth-eaten MacFarren translation) and the beautiful, non-droopy line:
The story goes that she discovered her high register when Richard Bonynge had her vocalize up above high C without telling her how high she was singing. After hearing this recording, I don't believe it for a second.