mamangam festival was celebrated on the bank of the river
Mamankam festival Māmānkam (Tamiḻ/Malayāḷam: Māmāngam/Mahāmaham or Māmākam) was a duodecennial medieval fair held on the bank, and on the dry river-bed, of Pērār (River Nil̥a, River Ponnani, or Bhāratappuḻa) at Tirunāvāya, southern India. The Hindu temple associated with the festival was Nava Mukunda Temple, Tirunavaya. It seems to have begun as a temple festival, analogous to the Kumbha Melas at Ujjaini, Prayaga, Haridwar and Kumbakonam.[1]
Triveni Sangam One such Triveni Sangam, in Allahabad, has the confluence of two rivers â€” the Ganges and the Yamuna and Saraswati River. The two rivers maintain their visible identity and can be identified by their different colours. The water of the Ganges is clear, while that of the Yamuna is greenish in colour.[1]