We went to Prayagraj becuase it’s near Triveni Sangam, the “three-river confluence” of the Ganges, Yamuna, and the mythical Sarasvati. If you go, consider bringing your swimming trunks!
Prayagraj is an ancient city and popular tourism destinations, second in terms of tourist arrivals, in Uttar Pradesh, after Varanasi. Prayagraj was previously called Allahabad.