Mahamaham, also known as Mahamagham or Mamangam, is a Hindu festival celebrated every 12 years in the Mahamaham tank located in the South Indian city of Kumbakonam in Tamil Nadu, India. This 20-acre square tank surrounded by Shiva mandapams is believed by Tamil Hindus to be ancient, and the holy confluence of nine Indian river goddesses: Ganga, Yamuna, Sarasvati, Narmada, Godavari, Krishna, Tungabhadra, Kaveri, and Sarayu, states Diana Eck – a professor of Comparative Religion and Indian Studies. On the day of the Mahamaham festival, the river goddesses and Shiva gather here to rejuvenate their waters, according to a legend in the Periya Purana. The Hindus consider taking a pilgrimage and holy dip at the Mahamaham tirtha on the day of Mahamaham festival as sacred. The event attracts chario