They were there in their thousands already by 5.30 yesterday morning and poured into Plaza de la Revolucion for hours afterwards, cheering, chanting and singing.
This was a much livelier and larger crowd than had been evident at any of the Pope's previous three Masses in Cuba. Estimates of its size ranged from a very conservative 200,000 to a probably exaggerated one million.
After much deliberation, a Cuban official said that in his opinion 700,000 were there. He had seen a million in the square for May Day celebrations and the like, but he didn't think yesterday's crowd was quite that big. Then someone said one of the major press agencies was going with the 200,000 figure, which struck everyone as ludicrous.
They were different from the other crowds in other ways, too. They were far more spontaneous, for instance, starting the chants with "Juan Pablo amigo" themselves.
They told John Paul (amigo) that Cuba was with him. They sang by themselves, not led from a microphone on the altar, waving those hundreds of balloons, thousands of tiny papal and Cuban flags, larger Cuban flags, flags from just about every South and Central American country.
They held up banners of the virgin, posters of El Papa and banners proclaiming Totus Tuus etc.
Indeed, by comparison with Santa Clara, Camaguey, or Santiago de Cuba on Saturday, there was very little warming up done on yesterday's crowd. And what did take place was far more restrained than the over-the-top shrieking we had become familiar with before the other Masses.
The music, too, was different. It was of a more formal kind, as befits a capital city, perhaps, with none of the folk/salsa tuned hymns. Instead, yesterday we had a soprano, and Handel with care. There was also another excellent choir. Gone too was that plague of other days, the rarely spotted sole papal hand-clapper, whose favourite habitat tended to be as near the most powerful microphone present and whose favourite habit was regular interruption of the Pope's sermon. For all that lack of "encouragement" though, yesterday was, of all the events during this visit, most truly of the people. They dictated the pace, in an atmosphere which was always festive. And there could be no doubt but that they had fallen under the spell of "Juan Pablo's charisma". Again and again they chanted his name and cheered him but at no time more so than during his sermon.
They roared their appreciation when he criticised wealthy countries for growing richer out of the needs of the poorer ones. They clapped and cheered when he talked about freedom of conscience. And they were almost uncontrollable when he told them that the Church and the Pope "in his heart and with his words" were with all who suffer injustice.
"Viva, viva, viva, viva Papa Juan Pablo" they chanted, and could not be stopped. Eventually, and with the timing of the consummate performer he is, Pope John Paul interjected and told them in Spanish "The Pope is not against you applauding him. Every time you do it you give him strength." Then they went wild altogether. Meanwhile, sitting in the front row, Fidel Castro must have wondered to himself "how does he do it?" Indeed the contrast between Dr Castro's arrival and that of the Pope could hardly have been greater.
Fidel walked to his seat accompanied by friends and security men: passing by the crowds of people he did not respond one way or the other. Meanwhile, above all, Che and Jesucristo gazed into the distance looking like one of a kind. Both had long hair, both wore beards, and both had that same faraway look in their eyes.
Only Che's beret set him apart. Jesucristo dominated the square behind the altar where his sacred heart has been on view in a huge mural for almost a week. "Jesus Christ I trust in thee" read a message over his head, while beneath a wrought-iron outline of Che's features, on the walls of the Ministry of the Interior, was written "to victory always".
Other slogans dominating the square included "Peace is the work of justice" from the Pope, which was opposite the altar, and Venceremos (We will be victorious) with his back to the crowd on top of another government building.
Presiding over the entire scene was a great stone statue of Jose Marti, that Cuban patriot from the last century whom everybody has been quoting since the Pope arrived on Wednesday.
Cuba changed yesterday, but it's too early to say how utterly. At the Mass at Santiago de Cuba on Saturday, a young man there said of his people: "Cubans are not religious, but most are believers."
His interest in the Pope, as of probably the vast majority of Cubans, centred on just one thing, the help he could give in having the sanctions lifted.
That same young man said jokingly: "If the embargo is lifted, I will pray all the time." For condemning the sanctions this morning, as he did on his departure from Havana, "Papa Juan Pablo" will forever hold a special place in the hearts of all Cubans. Indeed all this week, it was possible to see their affection for him grow.
Initially it was rooted simply in their gratitude to him for being among them at all. But as the week progressed, they were moved more and more by his obvious suffering as he laboured through long Masses and closely written sermons in hot sunshine.
This emotion became most obvious on his visit to the shrine at St Lazarus on Saturday night. As the Pope went among the sick and the infirm to touch and bless them at the end of the ceremonies there, it seemed to many of those present that many of those he blessed were in far, far better shape than he was himself with his stick, his slow walk, his laboured speech, his tired, tired face and that one eye almost completely closed.
Their concern for him marked their faces and some indeed seemed close to tears. Watching him as they sang in the choir and as he shuffled through the sick, two young girls began to cry.