Friday marks the most important day for Hindu pilgrims in the enormous Ardh Kumbh festival taking place in the northern Indian town of Allahabad.
The new moon night, or Mauni Amavasya, is celebrated on Friday, making it the most auspicious day in the six-week-long Hindu bathing festival. Millions of pilgrims are attending.
The BBC News website's Geeta Pandey was there, giving regular updates on how the day progressed.
0954 local time (0424 GMT), Allahabad
Thousands of Naga sadhus or Hindu holy men plunged into the Ganges in the northern Indian town of Allahabad at the crack of dawn.
Their bodies smeared with ash, they were naked except for bright marigold garlands around their necks.
Most ran out after a quick dip at Sangam, the confluence of three of Hinduism's holiest rivers - the Ganges, Yamuna and the mythical Saraswati.
But some splashed around the calm waters lit up by the warm morning sun. One sadhu performed a few somersault tricks.
On the shore, fistfuls of grey ash were taken out of polythene bags and smeared on shivering bodies.
Out came the tridents, spears and swords. Cries of Har Har Mahadev rent the air as the Nagas raised their arms and danced.
The sadhus officially kicked off Mauni Amavasya, the most auspicious bathing day of the six-week-long Ardh Kumbh festival.
Elsewhere too, millions have been taking a bath in Allahabad.
Tens of thousands have spent the night out in the cold
Tens of thousands have spent the night out in the cold, huddled together by the river side, at times with nothing more than a thin shawl to keep warm.
Some of the luckier ones managed to build small fires and sat around them, singing religious hymns through the night.
Bathing for Mauni Amavasya officially began at 0615 am local time, but anticipating huge crowds, tens of thousands bathed through the night.
A constant stream of people are coming into and leaving the city. Many said they had walked at least 10 miles to reach Sangam.
It is like a sea of humanity, wherever you look, you see people, men, women and some children too, crammed against each other.
The entire mela area, spread over several square kilometres, has been turned into a pedestrian zone and traffic to the area has been stopped since Thursday afternoon.
So far, the movement is orderly. Barricades have been put up everywhere in the mela grounds, and thousands of policemen and paramilitary troops have been deployed to ensure things go smoothly.
1130 (0600 GMT), Allahabad
For the thousands of foreigners who are visiting the Ardh Kumbh mela, they have not just adopted a new religion.
They have also taken on new names and new identities.
At the mela grounds, we come across an English woman who goes by the name of Ganga Devi. Ganga is the Hindi name for river Ganges.
"I have been a sanyasin [Hindu nun] for 10 years," she says.
Ganga Devi has been a Hindu nun for 10 years
She's just taken a holy dip in the Ganges. How does it feel?
"Coming out of the Ganga, I felt very clean. Not just the body, a dip here also cleanses your inside. It's wonderful that such festivals are still held. With these festivals, the world is a better place," she says.
We ask Australian Jasraj Puri what his real name is. "It's been washed away along with my sins into the Ganges and now has gone into the Bay of Bengal," he jokes.
For this physiotherapist who worked in Australia and Britain before a search for something more meaningful - "inner happiness", as he says - brought him to India 10 years ago.
He joined an ashram and has made Rajasthan his home.
"I'm visiting the mela to have a dip in the river and hear the saints, the holy men. Get their blessing," he says.
But you've heard them many times. Don't they repeat the same things all the time?
"Yes, but we never understand. Do we?" he asks.
We still don't know what his real name is.
Until a few years ago, foreigners coming for a dip in the Ganges were a rare sight.
Today, special tour groups are organised for them and special camps are set up for them at the mela grounds.
Here, one can hear myriad accents - from Italian to Japanese to American to British to French to Australian. You name it, they are all there.
Jasraj Puri is looking for 'inner happiness'
Some have even joined the ranks of the Naga sadhus.
We saw some European women who were part of the largest and most dreaded Naga camp - the Juna akhara.
An official for Juna akhara told us they have a couple of hundred foreigners in their group.
Unlike the men in this camp who go naked, these women were wrapped in saffron robes.
1320 (0750 GMT), Allahabad
Naga sadhus have a reputation for being unfriendly - traditionally they have shunned the media and any kind of publicity.
Before their processions arrived at Sangam, anxious policemen told pesky photographers to keep a low profile.
Naga sadhus have a reputation for being unfriendly
"The Nagas don't like cameras, they have been rough in the past, and you can get hurt if not careful," one officer told us.
But in the changed media environment in India today where dozens of news and spiritual channels have become immensely popular, even these holy men seem to have realised the importance of the camera.
Dozens of ash smeared naked men, with long dreadlocks and marigold garlands around their necks, waved at us and demanded that we take their pictures.
As we clicked away furiously, they raised their tridents and swords and danced before us.
Minutes later, two sadhus walked up to me and asked if my camera was real.
Since it was, I took a picture of them and showed it to them on the viewfinder. They went away beaming.
Another sadhu demands a cigarette of me. I tell him I don't smoke. He goes away disappointed.
There are several interesting offers.
Some of them suggest that I become a Naga and join their akhara.
A young sadhu asks if I will pose for a photo with his group.
I decline him politely. I'm not sure it will be appropriate for family viewing.
1403 (0833 GMT), Allahabad
Brisk bathing is being reported from all the 29 ghats (bathing platforms/steps).
Officials say 15 million pilgrims have already taken a dip in the Ganges since the early morning.
They expect the number of bathers to cross 20 million by evening.
The crowds at the ghats are so thick that even after several hours, many people are still waiting for their turn.
One pilgrim, Babloo Kesharvani, is disappointed. His attempts to have a bath this morning have been unsuccessful.
Million of pilgrims have already taken a bath
"The policemen kept diverting us. So I visited the temple near the river and came back. I'll try again in a few hours," he says.
Shri Mahant Vindgiri explains why everyone wants to have a bath in the Ganges today.
"The planetary alignment is such that sun rays, when they fall on the Ganges, turn the river water into nectar. So bathing here today is equivalent to drinking nectar," he says.
1627 (1057 GMT), Allahabad
The crowds of bathers are thinning down, but thousands are still waiting for their turn for a dip in the river.
Intizar's family took the parrot along for a dip too
I am told bathing will go on through the night. Boats carrying pilgrims waiting for a dip have fanned out across the river.
The majority of the crowds have finished bathing and have moved on to the streets. There are tens of thousands of pilgrims walking the streets and doing some last minute shopping for souvenirs and sweets.
Amazingly, many pilgrims are still arriving for the holy dip.
Sheshnag Giri and Kesar Giri, for example, have just arrived from Mumbai. The couple undertook a day-and-half journey for the bath.
"This is the number one religious place in the world. The significance of the Ganges is unmatched," the couple say.
On the way back I run into a 10-year-old boy carrying a cage containing a wet pet parrot.
Intizar tells me the family took the parrot along for the bath - "We all had a dip in the river, including the bird. We always take our parrot along," he said.
1930 (1400 GMT), Allahabad
Eighteen million have washed away their sins, and officials say at least two million more will be able to take the holy dip before the day is over.
The festival goes on into February
They say at least 200,000 people are waiting in trains and vehicles outside the borders of Allahabad to get in.
At the same time, thousands are leaving the mela grounds and the town, making space for the new arrivals.
So is a trip to Sangam worth its while?
Yes, is the overwhelming response from the pilgrims.
Having walked for miles and spent a night out under the stars, many do seem tired.
But their faces show contentment.
On the streets the crowds are so thick in certain places that you cannot break rank, you move with the flow.
But there are no frayed tempers, no shoving or jostling.
Many are carrying their belongings on their heads.
While walking, they hold hands or each other's clothes to avoid getting separated.
The Bhule Bhatke shivir, or the "lost and found camp", at the mela grounds has received more than 19,000 people so far on Friday.
A spokesman for the camp, Niraj Tiwari, tells me: "Most of them have been restored to their families. But people are still being brought here by our volunteers and once we make the announcements, their families come and claim them."
Their work will go on for many more hours, he says.
2000 (1430 GMT), Allahabad
It's night now, the temperature has dipped, and the bright lights around the mela grounds have been switched on.
"It's a very good mela, very well organised," says Shambhu Lal, who lives in Banda district.
Rajendra Prasad, who has come from Sant Kabir Nagar district with 15 family members, says the trip cost each one of them 350 rupees ($8).
A substantial amount for a villager in northern India , but he has no regrets.
"We have seen Ganga maiya," he says, as he prepares to board his bus to go back home.
Ganges is revered as a goddess, and it is often called maiya or mother.
And all those who are leaving are not going empty-handed. They are taking a bit of the Ganges with them.
Many of them are carrying bottles or cans full of Ganga-jal - sacred water from the Ganges.
Ghanshyam Bhardawaj who works as a driver in Delhi, explains the significance: "We always keep Ganga-jal at home. A few drops are used for worship, when someone is dying, a few drops are put their mouth, no religious ceremony is complete without this sacred water."
It's not uncommon to find some Ganges water in Hindu households across the length and breadth of India.
As the popular Hindi saying goes: "If you have faith I am Mother Ganges, but if you are a non-believer, I'm just flowing water."
The millions of pilgrims have shown that they do have the faith.