The Real Teatro di San Carlo (English: Royal Theatre of Saint Charles) is an opera house in Naples, Italy. It is located adjacent to the central Piazza del Plebiscito, and connected to the Royal Palace. It is the oldest continuously active venue for public opera in Europe, opening decades before both the Milanese La Scala and Venetian La Fenice theaters.
https://en.wikipedia.org/wiki/Teatro_di_San_Carlo

The Upper Crust of Naples

I said I knew nothing against the upper classes by personal observation. I must recall it! I had forgotten. What I saw their bravest and their fairest do last night, the lowest multitude that could be scraped up out of the purlieus of Christendom would blush to do, I think. They assembled by hundreds, and even thousands, in the great Theatre of San Carlo, to do--what? Why, simply, to make fun of an old woman--to deride, to hiss, to jeer at an actress they once worshipped, but whose beauty is faded now and whose voice has lost its former richness. Every body spoke of the rare sport there was to be. They said the theatre would be crammed, because Frezzolini was going to sing. It was said she could not sing well, now, but then the people liked to see her, anyhow. And so we went. And every time the woman sang they hissed and laughed--the whole magnificent house--and as soon as she left the stage they called her on again with applause. Once or twice she was encored five and six times in succession, and received with hisses when she appeared, and discharged with hisses and laughter when she had finished--then instantly encored and insulted again! And how the high-born knaves enjoyed it! White-kidded gentlemen and ladies laughed till the tears came, and clapped their hands in very ecstacy when that unhappy old woman would come meekly out for the sixth time, with uncomplaining patience, to meet a storm of hisses! It was the cruelest exhibition--the most wanton, the most unfeeling. The singer would have conquered an audience of American rowdies by her brave, unflinching tranquillity (for she answered encore after encore, and smiled and bowed pleasantly, and sang the best she possibly could, and went bowing off, through all the jeers and hisses, without ever losing countenance or temper:) and surely in any other land than Italy her sex and her helplessness must have been an ample protection to her--she could have needed no other. Think what a multitude of small souls were crowded into that theatre last night. If the manager could have filled his theatre with Neapolitan souls alone, without the bodies, he could not have cleared less than ninety millions of dollars. What traits of character must a man have to enable him to help three thousand miscreants to hiss, and jeer, and laugh at one friendless old woman, and shamefully humiliate her? He must have all the vile, mean traits there are. My observation persuades me (I do not like to venture beyond my own personal observation,) that the upper classes of Naples possess those traits of character. Otherwise they may be very good people; I can not say.