LA JONQUERA, Spain -- She had expected a job in a hotel. But when Valentina arrived here two months ago from Romania, the man who helped her get here -- a man she had considered her boyfriend -- made it clear that the job was on the side of the road.
He threatened to beat her and to kill her children if she did not comply. And so she stood near a roundabout recently, her hair in a greasy ponytail, charging $40 for intercourse, $27 for oral sex.
"For me, life is finished," she said later that evening, tears running down her face. "I will never forget that I have done this."
La Jonquera used to be a quiet border town where truckers rested and the French came looking for a deal on hand-painted pottery and leather goods. But these days, prostitution is big business here, as it is elsewhere in Spain, where it is essentially legal.
While the rest of Spain's economy may be struggling, experts say that prostitution -- almost all of it involving the ruthless trafficking of foreign women -- is booming, exploding into public view in small towns and big cities. The police recently rescued a 19-year-old Romanian woman from traffickers who had tattooed on her wrist a bar code and the amount she still owed them: more than $2,500.
In the past, most customers were middle-aged men. But the boom here, experts say, is powered in large part by the desires of young men -- many of them traveling in packs for the weekend -- taking advantage of Europe's cheap and nearly seamless travel.
"The young used to go to discos," said Francina Vila i Valls, Barcelona's councilor for women and civil rights. "But now they go to brothels. It's just another form of entertainment to them."
There is little reliable data on the subject. The State Department's 2010 report on trafficking said that 200,000 to 400,000 women worked in prostitution in Spain. The report said that 90 percent were trafficked.
But police officials and advocates say that whatever the number of victims, it is growing. Thousands of women are forced to work -- often for even lower pay now, because of the economic downturn -- everywhere from fancy clubs and private apartments to industrial complexes and lonely country roads.
Europe woke up to the problem of trafficked women in the 1990s, as young women from the former Soviet Union began to arrive in large numbers, and it has spent much of the last decade developing legal frameworks to address the issue. But, some advocates say, this decade will test Europe's commitment to enforcing its new laws.
"The structures, by and large, are in place," said Luis CdeBaca, the ambassador who leads the State Department's Office to Monitor and Combat Trafficking in Persons. "Now it's time to take them out for a drive."
Fueling the boom in the sex industry in Spain are many factors, experts say, including porous borders in many parts of the world and lax laws. Until 2010, Spain did not even have a law that distinguished trafficking from illegal immigration. And advocates say arrests of traffickers and services for trafficked women remain few. The State Department's report on trafficking said that according to preliminary information, the Spanish government prosecuted 202 trafficking suspects and convicted 80 in 2010.
More important, some advocates say, is the growing demand for sex services from younger tourists. Of course, there is a local market. One study cited by a 2009 United Nations report said that 39 percent of Spanish men admitted having visited a prostitute at least once. It is widely accepted here for business meetings to end in dinner and a visit to a brothel.
But more recently, experts say, Spain has also become a go-to destination for sex services.
In La Jonquera, tucked behind an all-night gas station, is the newly opened Club Paradise, which, with 101 rooms, is one of the largest brothels in Europe. It caters in large part to young men from France, where many aspects of prostitution are illegal, and perhaps more to the point, buying sex is more expensive.
On a recent evening, one young man from Paris stood in the parking lot of Club Paradise, bragging about his sexual exploits while his friends looked on. The women, he said, did not talk about whether they were being forced to have sex.
"Maybe," he said. "But I think they are having a good time."
If any of them actually are, they would seem to be the exceptions. Thirty years ago, virtually all the prostitutes in Spain were Spanish. Now, almost none are. Advocates and police officials say that most of the women are controlled by illegal networks -- they are modern-day slaves.
The networks vary enormously, and shift constantly. Some are "mom and pop" operations out of Eastern Europe, like the one that controls Valentina. Others have far greater reach, like the Nigerian organizations that first began to surface in Spain in the last decade. Deputy Inspector Xavier Cortés Camacho, the head of the regional antitrafficking unit in Barcelona, said the Nigerian groups moved women through northern Africa to Spain, and then controlled them by threatening to rape or kill their family members back home.
But Mr. Cortés said that people of maybe a dozen nationalities were involved in the trafficking. Until recently, for instance, the police in Barcelona did not even realize that Chinese mafias ran prostitution rings in the city. Then they began noticing more and more advertisements for Chinese, Japanese and Korean women -- all of them, it turned out, Chinese -- working in a network of about 30 brothels.
The working conditions were brutal, Mr. Cortés said. On wiretaps, he said, "we listened to them complain that they needed to rest, they were in pain. But they had to keep working. One woman committed suicide after finding out she was H.I.V.-positive."
Some of the women are sold into the business by their families, Mr. Cortés said. The police came across one case in which Colombian traffickers were paying one family $650 a month for their daughter. She managed to escape, he said. But when she contacted her family, they told her to go back or they would send her sister as a replacement.
Of the 1,605 women identified in 2010 as victims of traffickers, the biggest number -- about 30 percent -- came from the Balkans.
Many tell a story much like that of Valentina, who hoped to earn enough money in Spain to build a house and live in peace with her children.
So far, she said, she has earned a bit more than $2,000. But she has not been allowed to keep any of it. "They say I eat too much," she said. "They are angry if I buy something to drink."
In the meantime, her cellphone kept ringing, and the threats from her former boyfriend kept coming, she said.
The visibility of prostitution has become an issue here. A battle has raged over whether to allow advertisements for prostitution in newspapers, but they remain legal and appear even in the most reputable papers.
After one Barcelona newspaper ran a series last year on sex acts conducted in plain view near a main tourist attraction, the boulevard Las Ramblas, the city council said it would ban street prostitution and expand services for the women.
In La Jonquera, Mayor Sonia Martínez Juli says the town, population 3,000, has few resources to help the women.
"We feel completely abandoned with this problem," she said.
Some politicians would like to see prostitution outlawed in Spain, though that does not seem imminent. Many women's groups say that this would only force prostitution underground, making it even harder to help trafficked women.
For now, prostitution is legal, though not regulated, in Spain. But pimping is illegal, so most brothels like Club Paradise operate more like hotels. It charges the women who work there about $90 a night for room and board.
José Moreno, one of the owners, said the women who worked there did so freely.
"Sometimes there is a problem with a boyfriend," Mr. Moreno said recently, as scantily clad young women began to gather at one of the bars inside his club, readying for a night's work. "But that is usually cleared up quickly."
Some weeks after the interview, however, Mr. Moreno was convicted on charges relating to smuggling Brazilian women into Spain to work as prostitutes. He was sentenced to three years in prison and is appealing the decision. The authorities say the women can seek help, but many are reluctant. On a recent evening, Valentina, speaking a mix of Spanish and Romanian, said she was unsure where to turn. She said she had already been to the local police, but had been told she had to go to the regional police in Figueres, about 15 miles away.
A few days later, she stopped answering her cellphone and could not be found at her usual spot along the road. Inspector Cortés said that she had indeed gone to the police in Figueres. But at the last minute, she refused to go to a shelter and left on her own.
Rachel Chaundler and Stefania Rousselle contributed reporting.
This article originally appeared in The New York Times.