prayagraj ( formerly called as prayag, also known as allahabad), is a city in uttar pradesh state of india. it is located where three ganges and yamuna and saraswati(mansatta) rivers join. this city is a holy city for hindus. it is best known for kumbha mela. this fair occurs every 12th year in prayagraj. the city was named "allahabad" by the mughal emperor akbar.