REPORTER: Patrick Abboud
Married men... 
GEPENG (Translation):  Sometimes I use a condom.
Cheating housewives... Government officials and prostitutes... 
PROSTITUTE (Translation):  I need money and they need me.
Most consider themselves devout Muslims, revelling in a mass ritual of adultery and sex. Welcome to Gunung Kemukus - otherwise known as Sex Mountain. Mardiyah runs a humble market stall in a Javanese coastal town. She rarely leaves her village, but she's travelled hours to be here today at Sex Mountain. 
MARDIYAH (Translation):  I come here to seek good fortune.
She's one of thousands of Indonesian pilgrims who travel to Central Java every month or so. They believe the magical powers of this mountain will make them rich. Mardiyah's husband passed away five years ago and she has struggled since financially. She's hoping divine intervention will help. 
MARDIYAH (Translation):  If I have good fortune, praise God, I will pay all my debts.
We're going with her to make sense of this mysterious custom. On face value, it would seem to be an ancient tradition riddled with contradictions. Mardiyah's calling a man she's hooked up with on previous trips to see if he's here again. Tonight is her lucky night. 
PARMAN (Translation):  Hello?
MARDIYAH (Translation):  I'll see you at the usual place in front of the grave.
Parman agrees to meet Mardiyah at the shrine on top of the mountain later, the shrine where this religious sex ritual began. Back in the 16th century, Javanese legend has it Prince Samudro had an affair with his stepmother. They ran away and hid here on this mountain, Gunung Kemukus. But one day while mid-coitis they were caught and killed. They were buried here and the story goes you must have sex on the mountain every 35 days, repeat that process seven times, and blessings and wealth should come your way. 
You won't see this ritual anywhere else in Indonesia, or the rest of the Muslim world. It's a very Javanese blend of religious ideals, with Islamic, Hindu and Buddhist influences. Many of these pilgrims come from poor villages. Like Gepeng. He's a timber yard labourer and lives 300km from the mountain. He's married and has two children. There's a communal feast in his village today. Gepeng and his mates are eating up big before their long journey ahead to Sex Mountain. 
GEPENG (Translation):  If you are there, you look for a different partner, not the one you have at home. Historically, that is how it is.
The men lie to their wives, telling them they will be away working for the weekend. 
MAN (Translation):  I don't tell my wife, there is no way she will find out.
This woman is keeping her husband busy at home all weekend, warning if he was ever to cheat... 
WOMAN (Translation):  I would punch him like this! I would not let him if I knew.
It's hard to know whether these men are in it for the religion, the supposed riches, or simply the raunch. 
MAN (Translation): I just go there for the karaoke, not the ritual.
GEPENG (Translation):  We believe in God, it's for our business, so that...so our lives become more comfortable.
The men set off on scooters to seek their fortune. They arrive at sunset when the mountain comes alive. Excitement builds, flirting begins. There's karaoke and entertainment. Aphrodisiacs for sale. Sex shacks line the hillside. 
YULI (Translation):  Can you see me? Mister, show some mercy!
But before the fun, there are a couple of important steps that must be completed. First - prayers and offerings are made at the grave. Rather than praying to Allah, today Mardiyah is praying to the adulterous Prince Samudro. 
MARDIYAH (Translation):  Please grant me great financial good fortune, O Samudro, please help your servant to have good fortune. Please give me lots of money to pay my debts.
Then pilgrims must wash themselves at sacred springs. Once that is done, it's time for sex. Mardiyah disappears to find Parman. Yuli owns this makeshift motel that doubles as a sex shack and karaoke lounge. She rents out the rooms during ritual times and it's a thriving business. 
YULI (Translation):  Praise God, it's going well and getting better.
She attributes her success to the fact she completed the ritual years ago. 
YULI (Translation): I'm a Muslim, God himself gives us the opportunity. Our sins or wrongs, no matter how bad, can be remedied.
There's hundreds of little backrooms in the mountain for rent. In this space here, there's 20 rooms, ten on either side. They're all occupied at the moment apart from the one that I'm rested up against and the one opposite me. There's women with hijabs walking in, Muslim men with head pieces walking in and out. 
PROFESSOR KOENTJORO SOEPARNO, GAJAH MADA UNIVERSITY (Translation): It is a strange thing, it's a paradox. There is a mosque but around it is a place for having illicit sex.  They pray and say "Amen", the prayers are Islamic.
Professor Koentjoro has been studying Sex Mountain for more than 30 years. 
PROFESSOR KOENTJORO SOEPARNO (Translation): It is hypocritical.
Government authorities are loath to admit - there is sex going on here. The gatekeeper employed to oversee the mountain ritual is adamant the sex is not compulsory. 
GATEKEEPER (Translation):  I have never said that it is a condition of the pilgrimage, it is what they want to do. Pilgrims should come here with pure hearts and clean bodies.
If they can't find a sex buddy, they will happily pay for one. 
PROFESSOR KOENTJORO SOEPARNO (Translation): I think the idea this is a place of prostitution needs to be got rid of, if they want to improve it and make it more about the ritual behaviour, that is okay. But don't make it a place for legalised prostitution.
With more men than women coming here, it's grown to become prime territory for commercial sex workers. 
PROFESSOR KOENTJORO SOEPARNO (Translation): The government facilitated the prostitution there.
Behind that red curtain are rooms and girls for hire. I'm wearing a hidden camera. Within minutes I'm propositioned. 
MAN:  You want this?
REPORTER:  Sure.
MAN: Okay?
REPORTER:  Yes, do we go in the room? Do I have to pay her first?  How much do I give her?
Moments later I'm invited out back by the girl in yellow. I have to pay her the equivalent of around 30 Australian dollars. We enter a cubicle. She takes her clothes off. I explain I don't want to have sex. She agrees to just talk. 
REPORTER: How many men have you had today? 
PROSTITUTE (Translation):  Today I think is seven.
REPORTER:  Seven today, oh, it's many. 
PROSTITUTE (Translation):  I have a family and my husband is not here, I have a household to support so I need the money.
REPORTER: Do you think it's wrong that Islamic men come to have sex with you? 
PROSTITUTE (Translation):  What is clear is that they have a need. I need money and they need me.
REPORTER: When the men come, do they use condoms? You don't worry that you maybe get sick?
PROSTITUTE (Translation):  Well, yes I am worried. Yes, I am scared.
PROFESSOR KOENTJORO SOEPARNO (Translation): The Islamic religion forbids it but they don't want to know that because they are more interested in profit - they leave religion behind.
The reality is the local government makes a huge profit from Sex Mountain. They charge the stalls to set up shop and the pilgrims pay a toll to enter the site. At around 5,000 rupia or 50 cents a pop for entry, with up to 10,000 pilgrims coming every 35 days, that's big business in Indonesia. So it's not surprising officials and religious leaders turn a blind eye. At sunrise you'd be forgiven for thinking nothing happened here. The shrine is closed and the sex shacks are empty, but the working girls are still here. 
WOMAN (Translation):  This is an agreement to have an HIV test. Information on HIV, the benefits of an HIV test.
This community health clinic at the entrance to the mountain is open once a week. 
DR YUSINARTO (Translation):  Most of the sex workers here have contracted sexually transmitted diseases.
Dr Yusinarto has been coming to treat patients for years. He says the religious ritual here is a major contributor to the hike in sexually-transmitted diseases.
DR YUSINARTO (Translation):  With HIV/AIDS, we are finding a lot of cases, there is definitely an upward trend. They haven't acknowledged it, but what is the best way to say this? They know about it.
PROFESSOR KOENTJORO SOEPARNO (Translation): The government could ban it, but people would still come. The government can't stop them, even if for example, Islamic extremists went there, I don't think they could stop it because the locals would gang up on them.
Mardiyah has been in touch to tell me she and Parman have slept together. She admits she'd like to see him away from the mountain as well, but he's married and his wife isn't happy about their ritual arrangement. 
MARDIYAH (Translation):  He is still married and that is a problem for me, sometimes his wife gets angry.
PROFESSOR KOENTJORO SOEPARNO (Translation):  What happens sometimes is that the woman falls in love with this man and they have an affair, which takes place elsewhere.
It's hard to ignore the glaring contradictions at play here, but these pilgrims place their trust firmly in the custom. Like Mardiyah, most are convinced Sex Mountain has changed their life for the better. 
MARDIYAH (Translation):  Praise be to God, after seven visits, even though I have a few debts, I am paying them off. Whatever I sell makes a profit, even if it is a small one - even though it's not much, I am grateful to God and to this place.
Reporter/Camera
PATRICK ABBOUD
Fixer/Translations
REBECCA HENSCHKE
Second Camera
BUDHI SANTOSO
Producer
MEGGIE PALMER
Editor
DAVID POTTS
Graphics
MICHAEL BROWN
Translations
MELANIE MORRISON
Translations/Subtitles
ROBYN FALLICK
18th November 2014