Prayag is where two or more rivers meet. When Alaknanda and Bhagirathi meet they call it Ganga. While rafting in Rishikesh, I had an opportunity to dive into river Ganga and swim for a while. Since river water is cold and its about 80 feet deep, I had to put on the safety life jacket.
I had to dip inside numerous times while swimming. It is said, river Ganga will purify a person both physical and mental if you dip 3 times. I am surely a changed person after that experience.