Birgit Nilsson soaring top notes in her greatest live "Curse Scene" (1974)

Quite late into her career (aged 55 here), Nilsson still had the incredibly focused top notes we expect from her (and still on pitch in this year) and maybe even a somewhat denser sound than earlier. This is, in my opinion, her greatest performance of this scene.
Richard Wagner "Tristan und Isolde".
Isolde - Birgit Nilsson
Brangaene - Michèle Vilma
Conductor - Erich Leinsdorf
Metropolitan Opera House
30th January 1974, New York