Kumbh Melaa is a mass Hindu pilgrimage in which Hindu gather at the River Ganges, or River Godaavaree or River Kshipraa or Sanagam, where bathing for purification from sin is considered especially efficacious. The festival is regarded as the biggest religious gathering in the world. Kumbh is a Sanskrit word which means pitcher or pot, and Melaa means festival or fair, so Kumbh Melaa means the fair of pot, thus this is the fair of Amrit pot.

--In 2001, more than 40 million people gathered on the main bathing day at Sangam, Allahabad, UP, breaking a world record for the biggest human gathering for 55 days.
--Ardh Kumbh Melaa - In 2007, about 70 million people gathered for Ardh Kumbh Melaa in Allaahaabaad.
--In 2010 also, about 70 million people gathered for Kumbh Melaa in Haridwaar.
--The current 2013 Kumbh Melaa is Poorn Kumbh Melaa and it began on 14th January, on Makar Sankraanti day, at Allaahaabaad, About 100 million people are estimated to attend it.
--The next Kumbh Melaa will be held in Ujjain in 2015, on the banks of River Kshipraa. The Kumbh at Ujjain is called Sinhasth,

Myth About Kumbh Melaa
According to medieval Hindu theology, history of Kumbh Melaa can be found in several religious books, such as in several Puraan - Bhaagvat Puraan (Bhaagvat Puraan, 8/3-4), Padm Puraan (here this story comes two times, once in Padm Puraan, 1-Srishti-5  and second in Padm Puraan, 5-Uttar-37), Vishnu Puraan (Vishnu Puraan, 1-Pratham-3), Vaalmeeki Raamaaayan (V-Raamaayan, 1/14/45), Mahaabhaarat ( Mahaabhaarat, G-0-Prolog/6). It is linked with the Saagar Manthan story,

Its origin can be sought from the very olden times. Once Durvaasaa Rishi was coming from Bhagavaan's court carrying a flower garland in his hands. He met Indra coming from opposite side riding on his Airaavat elephant. He considered Indra worthy of that sacred garland, so he threw that garland towards Indra. Indra caught it in his hands, but in his pride he threw that garland on his elephant. Elephant had thrown it on the ground by his trunk and crushed it under his feet. Seeing this bad treatment to his Divine garland, Durvaasaa Jee got very furious. He immediately cursed Indra - "You have insulted the Divine garland like this, you will lose your wealth, grace. kingdom and prosperity very soon." So according to the curse of Durvaasaa Muni Indra lost all his prosperity and kingdom.

Indra got very sad so he went to Vishnu and told Him his saga. Vishnu suggested him that he should extend friendship with Daitya Raaj Bali and inspire him to churn the Milky Ocean (Ksheer Saagar) to get Amrit and other things which will be distributed between both of them." Vishnu further explained to him that he should not run after small small things coming out from the Sea. Indra agreed and got Bali also agreed on those conditions. Bali also got agreed and both Devtaa and Asur came to Ksheer Saagar. As Vishnu had directed Indra, they put the Mandaraachal Parvat as the churning rod, and took Vaasuki Naag as the churning rope. They could not move Mandaraachal Parvat themselves so Vishnu helped them. he kept it on His Garud and established it in the Sea. Now they started churning the sea. But the Sea was very turbulent so the Mandaraachal Parvat was shaking all the time. Vishnu again came to rescue. he incarnated as a Kashchap (Tortoise) and kept the Parvat over His back. But still the Parvat was not stable, so again Vishnu helped them and kept His hand over it to make it stable. Then only the churning got started. It is said that 14 various gems came out of the Sea. Their list varies in all the sources where Saagar Manthan story has been described - see the list of these gems HERE.

As soon as the Amrit came out of the Sea, both Devtaa and Daitya ran to snatch the Kumbh (pitcher or pot) of Amrit from Dhanvantari's hands. Since Daitya were more powerful, they snatched the pot from Dhanvantari's hands and ran away. Seeing this Devtaa remained helpless. Vishnu again came to rescue to Devtaa. Daitya saw a very beautiful woman coming to their side. She was Vishnu's Mohinee incarnation. She mesmerized Daitya, took the Amrit Kumbh from them and started distributing Amrit to both of them. But how could Bhagvaan give Amrit to Daitya? Mohinee set them in two lines - Devtaa and Daitya, and started distributing Amrit to Devtaa and liquor to Daitya.

Killing of Raahu
Raahu named Daitya had known Mohinee's trick. he quietly got up from his own line, assumed Devtaa's form and sat among Devtaa, between Soorya Dev and Chandramaa. When Mohinee came to give Amrit to Devtaa, She gave some to Raahu also not knowing that he was a Daitya in the form a Devtaa. In the meantime Soorya and Chandramaa recognized him as a Daitya and told this to Mohinee. Mohinee took out Her Chakra and cut the neck of Raahu immediately. But by that Raahu had gulped some Amrit, that is why he had become immortal. Now Raahu's body was divided in two parts, and because of drinking Amrit, he did not die, rather both parts of his body remained alive. His head became known as Raahu and his trunk was called Ketu. Brahmaa Jee gave his both the parts the status of Graha (planets). Thus they are not any visible Graha, but they are only shadow planets. Since that day Raahu has the enmity with Soorya and Chandramaa. Now he is after them and whenever he gets chance he tries to afflict them by swallowing them - on Amaavasyaa (New Moon day) and Poornimaa (Full Moon day) respectively, which we call Soorya Grahan (Solar Eclipse) and Chandra Grahan (Lunar Eclipse) day.

What Happened to Amrit Kumbh?
Seeing all this, Daitya had started fight with Devtaa. Meanwhile Amrit Kumbh was lying unattended. Lest Daitya take it again, Vishnu's ride Garud Jee took it and flew away. Devtaa and Daitya fight continued for 12 Divine days (12 human or solar years), and all this time Garud Jee continued to fly carrying the Amrit Kumbh. When he got tired he used to keep the Kumbh and took some rest. Thus during these 12 days he kept the Amrit Kumbh at four places - Haridwaar, Allahaabaad, Naasik, and Ujjain, near Gangaa River, Sangam, Gdaavaree River and Kshipraa River respectively. Since he kept that Kumbh at these four places at a certain time, these places are famous as Kumbh places and at those times a Kumbh Melaa takes place to have a share of that Amrit. After the Devtaa and Daitya fight was lover Garud Jee brought the Amrit Kumbh to Vishnu.

First Recorded Account of Kumbh Melaa
The first written evidence of the Kumbh Melaa can be found in the accounts of Chinese traveler, Huan Tsang or Xuanzang (602-664 AD) who visited India in 629-645 BC, during the reign of King Harsh Vardhan. However, similar observances date back many centuries, when the river festivals first started getting organized.

The major event of the festival is ritual bathing at the banks of the river in whichever town it is being held that is, Gangaa in Haridwaar, Godaavaree in Naasik, Kshipraa in Ujjain and Sangam (confluence of Gangaa, Yamunaa and mythical Saraswatee) in Prayaag (Allahabad). Naasik has registered maximum visitor to 75 million. Other activities include religious discussions, devotional singing, mass feeding of holy men, women and the poor.

Kumbh Melaa is the most sacred of all  pilgrimage. Millions of people come to these places to take a dip. It is regarded the largest religious gathering which takes place every 12 years. Naagaa Sanyaasee don't wear a single cloth even in severe winter and they take bath in Ganges' cold water. In 2013 it is going to take place at Allahabad, at Sangam, Uttar Pradesh, India, from 14th January to 10th March.

Mark Twain wrote after attending a Kumbh Melaa in 1895 - "It is wonderful, the power of faith like  that, that can make multitudes upon multitudes of the old weak and the young and frail enter without hesitation or complaint upon such incredible journeys and endure the resultant miseries without repining. It is done in love, or it is done in fear, I do not know which it is. No matter what the impulse is, the act born of it is beyond imagination marvelous to our kind of people, the cold whites."

Every time many celebrities come from all over India, even people come from many foreign countries too. This year, in 2013, people from some 100 countries are coming there. In the past famous Hollywood actress and singer Madonna and Hollywood actress Angelina Julie have visited Kumbh Melaa from the USA. This year Hollywood actress Catherine Zeta-Jones and Hollywood actor Richard Gear are going to visit it.

Dates of Kumbh Melaa
Kumbh Melaa is celebrated at different locations, depending upon the position of the Jupiter planet and the Sun.
--When the Sun is in Aries Sign (Mesh Raashi), and Jupiter is in Aquarius (Kumbh Raashi) it is celebrated in Haridwaar
--When the Sun is in Capricorn Sign (Makar Raashi), Jupiter is in Taurus Sign (Vrishabh Raashi), and it is celebrated in Prayaag
--When the Sun is in Leo Sign (Sinh Raashi), and the Jupiter is also in Leo (Sinh Raashi) it is held in Tryambakeshwar (Naasik, Poonaa)
--When the Sun is in Scorpio Sign (Vrishchik Raashi), and the Jupiter is also Scorpio (Vrishchik Raashi) it is celebrated in Ujjain (MP)
Each site's dates are calculated are in advance according to these combinations of the Sun, Moon and Jupiter.

This data can be presented in table form like this--

Most Significant Days During Kumbh Melaa of 2013
Makar Sankraanti - A Holy bath during this period carries special significance. Those who take a holy bath in the rivers Gangaa, Yamunaa, Godaavaree, Krishnaa and Kaaveree acquire pious credits.

Paush Poornimaa - The day occurs when the Moon is full in the Hindu month of Paush. This is the last Full Moon of winter. By this time, the Saadhu and hundreds of thousands of pilgrims arrive at the Kumbh Melaa.

Maunee Amaavasyaa Snaan - For the holy men and women, this is the main bathing day. New members to various holy monastic orders receive their first initiation on this day.

Basant Panchamee Snaan - This is the 5th day of the lighted half of the lunar month (Shukla Paksh) and is the beginning of spring in North India.

Rath Saptamee Snaan - Rath Saptamee festival is observed on the 7th day of Shukla Paksh in the Maagh Month (January–February) in the traditional Hindu calendar.

Bheeshm Ekaadashee Snaan - On this day, Bheeshm Pitaamaha, the oldest, wisest, most powerful and most righteous person belonging to the Kuru dynasty (approximately over 5000 years ago), narrated the greatness of Lord Krishn through Vishnu Sahastra Naam to Yudhishthir, the oldest brother of Paandav.

Types of Kumbh Melaa
There are mainly five types of Kumbh melaa --
(1) Annual Maagh Melaa - Every year people go to River Gangaa in Haridwaar or at Sangam in Allahabad to take bath for the whole month of Maagh.
(2) Kumbh Melaa - every 3 years -
(3) Ardh Kumbh Melaa - every 6 years The Ardh Kumbh Melaa is celebrated, every 6 years in Haridwaar and Allaahaabaad;
(4) Poorn Kumbh Melaa - in 12 years - the Poorn (Complete) Kumbh Melaa takes place every 12 years - at four places - Allaahaabaad, Haridwaar, Ujjain, and Naasik.
(5) Mahaa Kumbh Melaa - in 144 years - The Mahaa Kumbh Melaa which comes after 12 Poorn Kumbh Melaa (after 144 years) is held only at Allahabad. The last one took place at Allaahaabaad in 2001 with 60 million people attended it.

Dates of Some Old Kumbh Melaa
1892 at Haridwaar - cholera spread and took many lives
January 1894, at Allahaabaad
1903 recorded 400,000 people attended
1954 at Prayaag - stampede took about 500 lives and many were injured
1998, April 14, , at Haridwaar - 10 million people gathered
2001, Ardh Kumbh Melaa held in Allaahaabaad - 70 million people came to attend
2003, held in Naasik, Poonaa, from July 27 to September 2003 - about 100 people were killed and injured
2007, Ardh Kumbh Melaa at Allaahaabaad
2010, Poorn Kumbh Melaa in Haridwaar

2013, Poorn Kumbh Melaa in Allaahaabaad, January 14 to February 25. The following are the main Snaan days for it
14 January 2013 (Monday) – Makar Sankraanti
27 January 2013 (Sunday) – Paush Poornimaa
6 February 2013 (Wednesday) – Ekaadashee Snaan
10 February 2013 (Sunday) – Maunee Amaavasyaa Snaan (Main Bathing Day)
15 February 2013 (Friday) – Basant Panchamee Snaan
17 February 2013 (Sunday) – Rath Saptamee Snaan
21 February 2013 (Thursday) – Bheesm Ekaadashee Snaan
25 February 2013 (Monday) – Maagh Poornimaa Snaan
13 March 2013 (Wednesday) - Mahaa Shiv Raatri Snaan

--The Kumbh Melaa at Naasik in 2015 will also be Known as Sinhasth (as Brihaspati will be in Sinh Raashi) - August 15 to September 13.
--The Ujjain Kumbh Melaa 2016