Pope Benedict XVI met privately with Fidel Castro after saying Mass in Havana's Revolutionary Square -- the centerpiece of this trip -- before tens of thousands this morning.
During the morning service, with President Raul Castro and leading Cabinet members present, Benedict pushed for reform within the Cuban government.
"Cuba and the world need change, but this will occur only if each one is in a position to seek the truth and chooses the way of love, sowing reconciliation and fraternity," he said.
Fidel Castro did not attend the Mass -- he said he caught the entire visit on the TV -- but for a half-hour afterward he met with the 84-year-old pontiff.
Fidel Castro asked many questions and said that he'd dedicated his life to reflection and study. He also reportedly presented two of his sons to the pontiff and asked that Benedict send him books.
During their conversation, Benedict explained the changes made to the Liturgy and spoke of the importance of the trip.
Cubans Hope for Change
Catholics, especially Cubans, here and abroad, had hoped the papal voyage would spur further political and social change.
Before today's Mass, Benedict had been more muted in his public criticism of the country although before the journey, he'd said: "It is evident that Marxist ideology in the way it was conceived no longer corresponds to reality."
Fidel Castro handed the reins of government to his brother Raul in 2006 -- 53 years since the revolution that brought him to power and communism to the island.
During today's papal visit, he was a striking contrast to the young socialist soldier whose philosophy made him a hero to some and a boogeyman to others. Even as many of the world's other communist regimes toppled over the years, Castro held firm.
"The revolution is not negotiable," he told ABC News' Diane Sawyer in 1993. "Socialism is not negotiable."
In 1998, however, he did invite anti-communist Pope John Paul to the country.
Cubans said today that they remembered that visit and John Paul II's blunt call for freedom, human rights and justice for all.
Some said that Benedict seemed less effective. Even before Benedict had ended his visit, the government announced that there would be no political reform in Cuba.
"He's not going to make the change," one Cuban man told ABC News. "It's going to come from us. When we have the courage, everything can be changed."