Opera is a field of legends – and opera lost a legend when Birgit Nilsson died, apparently on Christmas Day. (The news is imprecise about this.) The Swedish soprano was 87. She’d had a long career, too, singing from her debut with Stockholm’s Royal Opera in 1946 until the mid-’80s. The world simply loved her – and it still does.

She’s often called the leading Wagnerian soprano of her generation, and that is probably true. For many, she is the definitive Brunnhilde, and one of the great Isoldes. And then there are her Strauss roles: Salome and Elektra, in which she crackled. She also sang Turandot (Puccini) – and many another role requiring indomitable strength.

Nilsson was the very embodiment of a certain kind of opera star. She was almost a Warner Brothers cartoon of the Wagnerian soprano: a Nordic block of granite – or maybe of ice – with a battleship voice. About that voice, there was debate: Some thought it was a bit harsh, metallic, unbending. Others thought this was nuts. All could agree that the voice was positively extraordinary.

What Nilsson had, beyond a doubt, was volume – as much volume as anyone has ever heard. I myself never had the privilege of hearing Nilsson in the flesh; those who did get kind of mystical when talking about that sound – particularly its volume. When they reflect on it, they can hardly believe that they heard it – that it was real.

A few years ago, I was talking to a famous opera singer about Nilsson, and this lady was waxing rhapsodic about that incredible sound. “It was so loud, it blew your hair back! It rattled your bones!” I asked, “But did you find her musical?” The singer thought for a second and replied, “She could be cold. But that sound! Jay, it was so loud! You had to have heard it – it was electrifying.”

One of the funniest things I have ever witnessed was the baritone Thomas Hampson imitating Nilsson in a master class. (That is, in a master class of his own.) Years before, he had attended a Nilsson master class, in which the soprano attempted to demonstrate high, soft singing. And in Mr. Hampson’s imitation, that sound was fabulously loud. She simply couldn’t help it.

I also treasure a remark made by Benita Valente, a soprano with a pure, lightish, lyric voice. She once said, “If I were Birgit Nilsson, just for a weekend, I’d sing for 48 straight hours, and peel the paint off the walls.”

The world at large last saw her 10 years ago, when she participated in the Metropolitan Opera gala honoring James Levine. (The conductor had completed 25 years with the company.) Nilsson – aged 77 – practically stole the show. She came on, gave a little talk, and said that, “since I’m a daughter of the Vikings,” she had to give a certain salute: Whereupon she sang Brunnhilde’s cries of “Hojotoho.” The place went absolutely mad.

Opera people love to tell stories, and Birgit Nilsson provided plenty of them. I’ll relate a few. The most famous one, of course, is her response to the question, “What does it take to sing Isolde?” “A comfortable pair of shoes.” (That opera – being by Wagner – is a marathon.)

And, do you know this one? At tax time, Nilsson is asked whether she has any dependents.”Only Rudolph Bing” (the general manager of the Met).

And this? Nilsson, in her retirement, is participating in a joint interview with another great soprano, also retired: Eileen Farrell. The latter is asked whether she ever heard Nilsson perform. She answers no. Says Birgit, “You really missed something!” It was merely true.

Over the decades, Nilsson made many, many recordings, and I will mention just one – not a particularly famous one, either. Actually, it’s a radio broadcast. I’m referring to the “Fidelio” (Beethoven) of January 1956, conducted by Erich Kleiber. Nilsson is Leonore, of course, and the voice was never more beautiful: It is refulgent, pliant, all-capable. Musically and dramatically, Nilsson is just about all you could want in this magnificent role.

But I must mention a second recording – this one, maybe the weirdest I own, or have ever heard. It’s Nilsson singing “I Could Have Danced All Night,” from “My Fair Lady.” And with whom does she sing it? With that famous Broadway maes tro, Herbert von Karajan, and that famous Broadway band, the Vienna Philharmonic. The sheer incongruity of this recording – Nilsson! Karajan! Lerner! Loewe! – is breathtaking. And so is the performance.

Nilsson revels in this song, toying with it, delighting in it. You can’t understand a word – English was not her language – but that’s okay. It is as though she is combining Eliza Doolittle and Brunnhilde.

The last line, as you recall, is, “I could have danced, danced, danced all night.” Nilsson is singing the song in C major. On the penultimate note – “all” – she goes up to a G. Uh-oh. She’s not going to do it. She just can’t – but she does. On that final word “night,” she nails a high C: a big, huge, heavens-filling C. Bizarro, but totally thrilling.

We often say of singers – and people generally – “She’s irreplaceable. There’s no one else like her.” Most of the time, this isn’t true. We may be unique to God, but we’re not necessarily unique in the opera house or on the concert stage, or in life. But it’s true of Birgit Nilsson: She was original, singular; there’s no one else like her; and who knows when we will see her like again?

But we have those recordings. And those who heard her without the aid of vinyl – or newer material – have their memories.