By Claudia Hammond
BBC News, Bangladesh
At first sight this seemed like any other port I had visited in Bangladesh.
Dusty streets packed with men and boys and long, long queues of trucks.
Bangladesh has a population of 152.6 million
The difference here is that once I had turned down a certain side street I had entered the biggest brothel in Bangladesh.
I was expecting to see one big building, but in fact it was more like a vast covered market with criss-crossing alleyways lined with fruit stalls, tailors and TV repairers.
I was with an NGO, the Bangladeshi Women's Health Coalition, which holds afternoon workshops on safe sex.
Usually in a situation like this they would have asked around in advance to find out whether anyone was prepared to be interviewed, but the open atmosphere here meant there was no need.
I was taken down an alleyway and ushered behind a curtain straight into a woman's bedroom.
A client enjoying a post-coital cigarette hastily fastened his sarong and scuttled off the bed, but the woman stayed to talk to me.
One sex worker came here 10 years ago to escape her violent husband.
Determined that her children will not grow up inside the brothel, she pays for them to be cared for in a local village.
Demand for sex workers has increased in recent years
But 350 children do live here, hiding under the bed when a client visits.
When the women get pregnant, many hope for daughters who in time will be able to join them working in the brothel.
The sex worker's room is one of the better ones, with a TV, a fan and a double bed covered in a sunflower-patterned throw.
She told me 1100 was the best time for business, when the ferry queues are at their longest.
One unexpected consequence of the rising water levels in Bangladesh is that river erosion has reduced the number of operable ferry berths, so men wait longer to cross, which in turn increases the demand for prostitution.
When I asked her if I could take her photograph, I guessed the answer might be No. But it turned out her initial reticence was because she had just seen a client and was not looking her best.
Your appearance is very important here. She spends two hours a day and a third of her earnings making sure she looks good.
The underage girls earn more, but because she is in her twenties she is paid 100 taka ($1.50) for sex, about the same you would pay for a couple of large bottles of fizzy drink.
Most people we met were happy to be interviewed. One even handed us fresh green coconuts with drinking straws - not easy to balance whilst holding a microphone, but refreshing nonetheless.
In the next room a client lying on the bed told me he was staying in the port overnight on business and that whenever he passed through he visited the same woman.
I asked him whether he was married. "Oh yes," he laughed, "but my wife doesn't know about this."
The women I met were all assertive and keen to tell me how they demand that men use condoms.
Some of the women have the power to do this, but there are also bonded sex workers who must do what their madams say.
They enter the brothel at an average age of 14 having been kidnapped, sold by step-mothers or tricked by their boyfriends.
One tells me she must see more than 25 clients a week - three during the day and then another each night.
Most feel they have no alternative but to stay
Ten years ago she was taken from her home in the south of the country.
In time she can buy her freedom, but will probably stay in the brothel to avoid destitution.
I was told stories of families who gave up searching for their kidnapped daughters after just one week, because once they had been in a brothel they would bring shame on their family.
This was such a grim place to visit that I found myself trying to look for any positives in the women's situation
The women themselves feel such shame that they often give their hard-earned cash to the beggars who wait in the alleyways.
Every single woman I spoke to told me she was planning to leave in a year or so, but in reality most feel they have no alternative but to stay.
Behind the brothel there is a small, green field, which is so peaceful that it felt a world away from what is happening inside. But I soon realised this is where any woman who cannot leave will end up.
Denied Muslim burial rights, the women have their own graveyard.
The brothel was such a grim place to visit that I found myself trying to look for any positives in the women's situation.
Perhaps there was a great sense of camaraderie. Perhaps they laughed together behind the men's backs?
But as soon as I asked, I realised I was wrong.
The woman just looked at me, and said what could possibly be good about living here? At the end of the afternoon I could just walk out and rejoin my BBC colleagues back on board the boat. She is still there.
From Our Own Correspondent was broadcast on Thursday, 17 January, 2008 at 1100 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.