HAVANA, Cuba – In the most concrete sign of warming relations between the United States and Cuba, President Barack Obama has concluded his historic visit to the island nation, the first for a sitting US leader in nearly a century.

As Obama stepped off the presidential plane ‘Air Force One’ at José Martí International Airport, he was greeted warmly by Foreign Minister Bruno Rodríguez, members of the Cuban Armed Forces who bestowed upon him full honors and a bevy of Cubans waving miniature flags of the United States and of their nation.

“This visit is of a historic nature as it has been just under 90 years since a US President has visited Cuba, but it is just the first step in new relations between our nations,” Obama said upon landing. “It is wonderful to be here and to be able to finally interact personally with the Cuban people.”

In a jam-packed first day, Obama visited the recently-opened Embassy of the United States in Havana and was then led around the streets of Old Havana and the city’s famous Malecón seawall by a local historian who served as his guide.

He then met with Cardinal Jaime Ortega, who was Pope Francis’ primary contact in Havana during the negotiations to normalization Francis inspired, at the Cathedral of the Virgin Mary of the Immaculate Conception in Old Havana.

Later, Obama met with Cuban leader Raúl Castro and then a group of dissidents and young businesspeople (back at the US Embassy), with whom he discussed politics and emerging (and future) opportunities on the island.

With Castro, Obama spoke of the decades of separation and hostility briefly but chose to focus on the present. Those differences, according to both leaders, still exist but are not insurmountable obstacles to firmly cementing the normalization of relations which began tentatively in October of 2014.

When the White House first announced Obama’s visit last month, it said that “in Cuba, the President will work to build on the progress we have made toward normalization of relations with Cuba – advancing commercial and people-to-people ties that can improve the well-being of the Cuban people, and expressing our support for human rights,” the press release continued.

Indeed, during the discourse with Castro, Obama reiterated that the “United States will continue to call for (and defend) universal human rights, including the right to freedom of expression, assembly and religion, on the island.”

Previously, during the initial warming of relations, Obama said that although he wished to set foot in Cuba on an official state visit, he said that it would not happen unless Cuba improves what Washington sees as a poor record of human rights and the detention of political prisoners.

While the US leader said that the human rights situation has not improved in his opinion, he still made the trip to Havana. The likely reason for this is his domestic situation: given that the US is in the midst of an electoral season that could very well bring in a new leader that will undo Obama’s improvement with Cuba, the US President is looking to cement the newly-rediscovered ties and make them as irreversible as possible by January.

On the other hand, Obama also said that in today’s world, there needs to be communication and dialogue between nations regardless of certain differences. He cited the fact that while the US officially denounces China’s government (among others) as authoritarian and accuses it of violating the human rights of its citizens, it still has had normalized relations with Beijing for decades now.

Castro, for his part, denied that there are political prisoners on the island and asked a US journalist who asked him the question concerning those allegedly detained to give him a “list of political prisoners’ names” so that they could be “immediately released before even nightfall.”

The following day of the historic visit, the first by a US leader since 1928 when Calvin Coolidge attended the 6th Conference of the Pan-American Union in Havana, saw another conference between Obama and Castro. The second conference, held at the Grand Theater of Havana, was preceded by the laying of wreaths at the monument to José Martí, Cuba’s national hero and founder of the nation, at Revolution Square while the national anthems of both nations were played by the Cuban military band.

This time around, Castro brought up the US embargo on Cuba, which is opposed by every nation in the world besides the US and its staunch ally Israel. The embargo, instituted in 1960, targets commercial, economic, and financial aspects of US-Cuba relations, which included the US threatening to cut off ties with countries who dealt with Cuba at one point.

The Cuban government has blamed the embargo for many of the more troubled aspects of the national economy and development and wants to see it lifted. On the other side of the coin, detractors of the Cuban government in the US have also asked the embargo to be lifted so that, as they say, Havana could stop blaming the embargo for its government’s own economic shortcomings.

“The trade embargo will be lifted, I am sure of it,” Obama said in response to Castro. “What I am not sure of is when this will take place,” added Obama, who has previously voiced his support for the lifting of the embargo.

In this instance, however, Obama’s personal feelings cannot play a role as the embargo can only be lifted by a congressional action, not by a presidential decree.

Economic reasons are the primary motives for why the US finally decided to restore relations with Cuba given that the European Union, China, Brazil, Russia and others recently became engaged with Cuba in negotiations concerning multi-billion dollar projects. If the US did not move quickly in normalizing relations (and does not move quickly in lifting the embargo), they would be left out of any possible future investment opportunities on the island.

Castro also brought up the nation’s wish for the eventual return of the land and coastline that currently houses the US’ Guantánamo Bay Naval Base (and the notorious prison) on the eastern coast of the island.

A chunk of territory and coastline some 120 square kilometers (45 square miles), the area has been leased to the US since 1903 under an agreement which Cubans say was made under extreme pressure, a fitting assertion especially since the the lease is for “as long as necessary” and Washington pays less than $5,000 a year for the territory through loopholes. The US has occupied the area since it invaded Cuba during the Spanish-American War (1898).

On this issue, Obama has favored closing the prison but has no congressional backing for such action. As for the return of the actual territory itself, the US leader did not make a statement, most likely because of the electoral timing and the fact that the issue of the prison and land return is divisive in the US.

Despite tense moments, the second meeting, which was more intimate, had a generally upbeat and friendly tone.

“I came here to bury the last vestiges of the Cold War in the Americas,” Obama said as he spoke of uniting factors between the two nations like a history of colonialism and slavery, the game of baseball and the vibrant presence the Cuban culture still retains in pockets of the United States including Miami, New York and other regions.

The US leader finally ended his stay in Havana by taking in a game of baseball, the most beloved US export on the island that is Cuba’s national sport.

The two leaders sat side-by-side at the Estadio Latinoamericano, filled to its 55,000-spectator capacity, to watch the Tampa Bay Rays of the US’ Major League Baseball play a friendly game against the Cuban National Team.

It was a family affair; Obama came with his wife, two children and mother-in-law, and invited with him Rachel Robinson, professor and the widow of famed Black baseball pioneer Jackie Robinson. Castro, whose wife died in 2007, was accompanied by son Alejandro and his toddler granddaughter, carried in the arms of Alejandro, and a grandson. Seated one row behind were Rodríguez, the Foreign Minister, and John Kerry, his US counterpart, and prominent diplomats and advisors from both sides.

After a somber start as there was a moment of silence for the victims of the Brussels bombings, the game became lively and so did the talking and joking between the two leaders. Shortly after, the two men were spotted speaking again as Castro personally saw off the first family as they boarded ‘Air Force One.’

Obama’s visit came over half a year after another monumental breakthrough was reached. In July of 2015, Cuba hoisted its flag above a stately mansion in Washington, D.C. for the first time since 1961 and the US returned the favor a month later as the Stars and Stripes were raised in front of an imposing building Havana’s famous Malecón seawall.

With two short ceremonies in both nations’ capitals, the diplomatic relations between Cuba and the US were re-established 54 years after then-US leader Dwight Eisenhower severed the ties shortly before he left office in late January of 1961.

Prior to the progress made recently, the US and Cuba, only 140 kilometers (90 miles) apart, had a very tense relationship set along the backdrop of the Cold War. Initially, Eisenhower cut formal diplomatic ties after Washington disagreed with former leader Fidel Castro’s economic and social policies that he instituted following the victorious uprising he led in 1959 against the US-backed dictatorship of Fulgencio Batista.

Eisenhower said after cutting diplomatic links that he “hoped” that the “historic friendship” between the two nations would be restored soon, most likely because he expected Cuban leader Fidel Castro to step down under heavy US pressure (or an invasion like the Bay of Pigs) or die from repeated US assassination attempts. Over half a century and 11 US Heads-of-State later, those diplomatic links were finally re-established.

At the behest of Pope Francis, diplomatic relations were restored; the Vatican confirmed that Pope Francis wrote lengthy letters to both Presidents Obama and Castro urging them to solve their issues for humanitarian reasons. The pontiff welcomed delegations from both countries to the Vatican in October of 2014 in which he tried to foster a “constructive dialogue on sensitive issues in the hopes of finding mutually satisfactory solutions,” an urge that the sides apparently took seriously given the results seen in the time following.