Havana  - Collapsed political systems, presidents who came and went, wars and attacks, broken alliances, rebuilt countries - 50 years of history unrolled across Latin America.

Yet Cuba and its revolutionary tradition have survived all of this, standing by its socialist continuity in the face of historical change.

Nothing is as it was on that January 1, 1959, when the fighters led by the young, bearded Fidel Castro made their triumphal entrance into the south-eastern city of Santiago de Cuba, proclaiming the victory of a revolution that was not yet socialist and that was later to gain a global clout out of proportion for such a small Caribbean island.

The previous night, dictator Fulgencio Batista had fled for the United States, leaving the island to the rebels. The young revolutionaries were planning to rebuild the whole system, but few would have imagined that their work would still be standing, albeit on somewhat shaky legs, 50 years later.

Complete victory came just eight days later: Fidel Castro entered Havana, dressed in the green fatigues which had already become a trademark of the revolutionaries.

His brother Raul, another constant of the Cuban Revolution, missed the victory photograph because he had stayed in Santiago. And so did the Argentine-born Ernesto "Che" Guevara, a rebel mythological figure who lives on to this day in legend.

Others were in the picture, like Huber Matos, but revolutionary history was later to erase them from its ranks because they did not fit the socialist ideal that was rising to prominence.

Indeed, many - like Matos, who served 20 years in prison in Cuba before going into exile - stress that socialism was not the plan when they took up arms in 1956, when 82 fighters led by Fidel Castro arrived in Cuba from Mexico on a yacht named Granma for the definitive assault on the Batista regime.

The "socialist character" of the revolution was officially proclaimed two years after the triumph - and after several attacks that Cuba blamed on the United States - on April
16, 1961.

"This is the socialist and democratic revolution of the humble, by the humble, for the humble," Castro said.

He thus cleared any doubts about his progressive rapprochement with the Soviet Union, which was seeking a foothold in the western hemisphere.

One day later, on April 17, 1961, the new revolutionary Cuba was getting ready for its first victory against "empire," the word used to describe the United States: in just 72 hours, the island repelled the arrival in Playa Giron (Bay of Pigs) of 1,500 organized anti- Castro activists supported by the CIA, most of whom were arrested.

Bad relations with the United States were sealed in that moment forever, or at least for the decades since then.

In January 1962, at the request of Washington, Cuba was expelled from the Organization of American States (OAS). And a month later US president John F Kennedy ordered an embargo that persists to this day and which Cuba claims has cost the island close to 100 billion dollars.

In October that year, the world watched in anguish as the Cuban missile crisis unfolded and brought the world to the brink of war: The Soviet Union had started to install on the island nuclear missiles aimed at the United States.

Under threat of a sea blockade and under extreme international pressure, the Soviets removed the weapons without consulting Cuba. This annoyed Fidel Castro, but that would not stop the Soviet Union from being the island's main support for the decades to come, until its collapse in 1989.

Over those decades, Cuba carried out an "internationalist campaign."

This had a military angle. Cuba participated in conflicts in Algeria, Congo, Angola and Latin America. Che died in October 1967 during his campaign in Bolivia.

It also had a medical side, with the deployment of thousands of Cuban doctors all over the Third World that has earned Havana the recognition of many other countries.

The collapse of the Soviet bloc threw Cuba into a profound crisis in the 1990s. The phase, which Havana termed the "special period," did not, as many hoped, bring down the Cuban regime. However, it did leave serious scars, particularly with regard to corruption and the "double standards" that the authorities continue to recognize as one of their main problems.

However, neither the collapse of the Soviet Union nor the transformation of China and Vietnam into socialist countries with market economies, nor the passage of 10 presidents through the White House - all with their plans against the Cuban regime - have brought Havana to drastically change its course.

Neither has the growing distance of intellectuals around the world from Cuban counterparts, nor the departure of hundreds of thousands of Cubans who have fled the island. More than 2 million now live abroad, and more than 11 million remain behind.

On July 31, 2006, many believed that change was finally about to take place: Fidel Castro astonished the world by delegating power to his brother Raul due to an unspecified illness. A year and a half later, in February 2008, Fidel Castro definitively gave up the presidency.

Raul Castro did make some "changes." He lifted restrictions on Cubans to lodge in luxury hotels on the island or to have mobile phones, and redistributed some idle land, for example, although many other topics were pending, including the elimination of restrictions on travel and the double currency that Cubans have to use to their detriment.

In political terms, Cuba recently signed two international human rights treaties - although they are yet to be ratified - and fixed its relations with Mexico, Brazil and the European Union, among others.

However, as regards ideology, Raul Castro has made clear his intention to persist on the socialist course delineated by his historic brother. (dpa)