On a recent evening at a highly-guarded location in north Tehran, a group of young men and women gathered to practice something exciting but deeply illegal: the tango. In recent years a dance class craze has swept the middle class and wealthier neighbourhoods of Iran’s cities, with young Iranians eagerly signing up to learn the samba, salsa, zumba, tango and other passionate dances that fire the imagination but involve some complicated steps.

‘Persian girls are natural dancers. We learn how to dance from the childhood, in front of the mirror, at parties and weddings,’ says Atefeh, a 21-year-old software engineering student in Tehran. ‘But they way we dance isn’t practiced, we’re not good dancers when it comes to duet dances like tango or samba.”

Like many young people who have joined the classes to practice their moves, Atefeh attends underground dance classes. She has been going for three years now and has had to change instructors four times, because some are “not as professional as they claim.” Others, she says, “think it’s too risky to continue the classes and shut them down.’

The price of the classes varies according to neighbourhood, with instructors in wealthy districts of Tehran such as Zafaraniye charging as much as 5,000,000 rials (£100 ) for 10 sessions. But in more middle class and working class neighbourhoods, sessions are typically a fourth of that price.

Classes draw participants across a wide age range, with matronly housewives there to lose weight to young girls whose families consider them talented enough in dance to pursue classes seriously.

Getting the Word Out

Because the state’s Islamic morality codes forbid unrelated women and men from mixing in private, dance classes are not openly advertised. Occasionally a pamphlet for a salsa class might be tossed on a doorstop, or stuck on a pole by a bus stop. But mainly news of the classes are spread by word of mouth, and participants bring along their friends and families.

Instructors also use closed Facebook groups to advertise classes, to gauge interest in a particular class and assess numbers when offering a new course. But even on Facebook they do not disclose the address to the dance studio, and instead ask those interested to contact them directly for more details.

Most classes are held in private homes or buildings, with trainers turning a conference space or parking garage into a studio by installing mirrors on the walls. Many hold classes in their living rooms, asking students to help re-arrange and then later put back furniture for the course.

Shake it, Shake it

But dance classes are not always underground. Many dance instructors register their classes at gyms and teach under the name of aerobics. The authorities have turned a blind eye to these studios and don’t seem to object to physical exercise combined with some music, as far as men and women do not mix.

Atefeh says the participants of the underground classes she attends are mainly young women. Occasionally some of their partners have shown up to learn a dance together, but young men, in her experience, don’t typically stick with the lessons.

‘They seem interested in dancing but I think there is still a taboo in our society around men attending dance classes’ she says.

There is one time, however, when couple dancing is in high demand, and that is around weddings. Dance instructors run a lucrative trade offering private lessons to couples before their wedding reception, typically the tango.

Iranian weddings, often lavish affairs that families go into debt to finance, involve a traditional raghs-e chagoo, or ‘knife dance,’ usually danced by the bride’s sister. Before the cutting of the wedding cake, a young relative dances elaborately with a knife and refuses to hand it over to the bride and groom unless they give her some money.

Mounir, a 21-year-old Tehrani who attends regular classes says jokingly the money that a girl can get by a good knife dance in a wedding would cover most of the dance class expenses.

Mounir is not interested in classic dances like tango or ballet. She attends hip-hop and belly dance classes (known as Arabic dance in Iran) just to shine more at parties. She says the classes she attends are informal. ‘People usually just wear casual clothes, mostly sportswear. Even for Arabic dance no one wears a long dress, just a scarf around the hips. In hip-hop courses, baggy trousers and loose T-shirts are more trendy,’ she says.

I asked her how her trainers, born and raised in Iran, have learned how to teach hip-hop dance. ‘My trainer says he has been going to dance classes since she was five, Mounir says, ‘but they mainly learn modern dances from music videos and also dance lessons on DVDs.’

One on One

‘My dance instructor always says she earns most of her income from private teachings,’ says Monir. ‘She says she sees our courses more as an advertisement so she can find more private customers.’

I asked her to explain more about these ‘private customers.’

‘In many occasions families are not against their children taking dance courses but they don't want them to take the risk and attend underground classes. So they ask the trainer to come to their house.’

I ask Atefeh and Monir if they see dancing as a form of income in the future, a potential career. Monir bursts into laughter and rejects it right away, but Atefeh starts to seriously think about it, ‘Why not? It’s an art and it keeps you healthy. And to be honest it can be a great source of income.’

Atefeh says she knows many western dances now but she can easily find a lot of students by teach Iranian traditional dances, especially Baba Karam.*

Dance classes are slowly ceasing to be a secret and guilty pleasure in Iran. Now even some private kindergartens offer dance classes for children as young as three. Instructors are still conservative and prefer to refer to their courses as ‘aerobics’, ‘rhythmic moves’ or even ‘losing weight with music’, but for thousands of people who attend the courses, it is nothing but dancing like nobody's watching.

*Baba Karam is a character dance that all Iranians know and love. It is a dance performed by both males and females at parties, weddings, and celebrations. Full of comical bravado, it is characterized by movements such as hip swings, finger snapping, neck slides and head bobbles, masculine stances and posturi