Did you know that one of the most famous notes in musical history was recorded right here in Mexico City? It was the night of March 7, 1951 and the singer was Maria Callas, just taking off on her meteoric rise to operatic stardom, was singing Aida at the Palacio de Bellas Artes.
Callas had been tempted by the opera's director, who told her that 19th century Mexican soprano Angela Peralta was famous for interpolating a high E-flat into the opera's Triumphal Scene.
She was also annyoed by the antics of tenor Kurt Baum who, during rehearsals and on opening night, held his top-notes in show-off fashion, ignoring signals from the conductor to straighten up.
During the first intermission, mezzo-soprano Giulietta Simionato who was singing Amneris, reportedly went to Callas's dressing room and said to the soprano: "Cara, per me...da il re-bemol!" ("Dearest, for me...take the E-flat!") and Callas agreed. Simionato told the other singers and the conductor of Callas's intentions but left the tenor in the dark. When the moment came and Callas latched onto the unwritten note, Baum went ballistic and swore never to sing with her again.
According to one first-person account, at the end of the second act, Bellas Artes 'se convertió en un manicomio' (turned into a madhouse). The audience was hugging and kissing one another, cheering wildly 'like at a bullfight', and waving handkerchiefs in the air.
The Mexicans adored Callas and when she was invited back the following year for more Aidas the public expected her to interpolate the E-flat again--and she didn't disappoint. The 1950 E-flat is remarkable though not as well-captured on tape as the 1951 when she hurled the note into the house like a javelin.
Here, in very primitive sound, is the finale of the Triumphal Scene from the 1951 Mexico City Aida (the famous note is around 4:40); Callas is Aida, Oralia Dominguez sings Amneris, Mario del Monaco is Radames and Giuseppe Taddei is Amonasro.
(I'm not sure if this one's from Mexico City, but it's even more insane: https://www.youtube.com/watch?v=sT2BMO5TlJY)
(Thanks to Oberon's Grove for historical background material)