Take an evening stroll down the Malecon, Havana's crumbling seafront promenade, and you will eventually come across a large crowd.
Get a little closer, and you will see that it is made up of young Cubans. All men.
The spot, just in front of the grand Hotel Nacional, has become the main meeting point for Havana's homosexuals.
The Malecon, a popular haunt for gay Cubans
The fact that they are there at all reflects a marked change in Cuban society.
In the 1970s, being openly gay on this communist island would have made your life extremely difficult.
Homosexuality, like religion, was considered "anti-revolutionary". Notoriously, some gays were forced to work in labour camps. Others fled the country.
Now homosexuals are tolerated, if not fully accepted.
There are no gay bars or discos in Havana - one reason why so many gay men congregate on the Malecon.
Most of those there when I visited seemed to accept that they are no longer victimised by the government. But they are becoming victims of another kind.
Two-thirds of all Cubans with Aids are homosexual men.
Fortunately the number is still very small. Cuba has one of the very lowest HIV infection rates in the world.
That is thanks to a controversial quarantine policy in the early 1980s, an excellent public health system, and a largely non-travelling, non-drug-injecting population.
But it is rising. And it is rising fastest among gay men.
Cubans who work with Aids patients have expressed concern that this still homophobic society is not doing enough to educate the people who are affected most by Aids.
Alberto Rosabal works at the Los Cocos Sanitorium, where many of those from Havana who have tested HIV-positive live. Eighty percent of the residents are gay men.
"I think that our society is not prepared to speak freely about gays, about gay activity, about the gay risk of having HIV," he says.
Cuban Aids posters tend to feature heterosexual couples
"Maybe it is because of our historic origins from Spain and Africa, but almost all the population have homophobia as a rule in their minds."
It is noticeable that in the lobby of Cuba's national Aids prevention office, there are several posters on display portraying attractive heterosexual couples. None showing gay men.
It is Havana's homosexuals themselves who are taking charge of informing their own community of the dangers of Aids.
Reluctance to use condoms
Most evenings a small group of them heads out to the city's parks.
In a project backed by Cuba's public health ministry, they hand out condoms and advice to the gay men that frequent the area. Many of those they talk to are prostitutes - young men taking advantage of one side of Cuba's expanding tourism industry.
Manuel, one of the volunteers, says that in a country so proud to be almost Aids-free, there is a remarkably casual attitude towards safe sex.
All Cuban men, he adds, are reluctant to use condoms - "a macho thing," he believes. "My work is to make sure people know the risks they are facing."
His is a small, but important, effort - trying to ensure that the battle which Cuba thought it had won, is not belatedly lost.
The following comments reflect the balance of views we received:
As a gay man I must commend Manuel on his efforts to help his fellow countryman.
Andrew, Queens, NY
I think in most if not all of the countries, gays are ignored in the fight against Aids. This is one area that should be looked very seriously. Congratulations to Cuba for the step that they took.
Nelly Marakalala, Mmabatho, South Africa
The situation of life for gays in Cuba is nothing new. I do remember when I went for the first time, the "balseros" time. This article is huge as it underlines the double moral, on one side the Ministry of Health promoting safe-gay-sex, but not doing anything into the general population.
Agustin Villalpando (Enkidu Magazine), Mexico City, México
It's amazing to me how we are so reluctant to confront the issue of HIV/Aids merely because of its connotations with homosexuality, as is the case in Cuba. There's almost this aura of "let them fend for themselves", rather then, "these are human beings, who are overwhelmed by persecution and have to deal with a deadly virus on top of that."
Dietrich Bouma, Framingham, USA
I believe financial cooperation among nations in the model proposed by secretary general Kofi Annan is very important. Also end sanctions and travel restrictions against Cuba to include them and their contribution to the international community.
Gil, Santa Cruz, USA