Allahabad is basically famous for Prayag which is one of the most sacred places according to the Hindu religion though there are other places like akbar forte, akshay batt, anand bhawan etc
I didn't get a chance to see the City much. But my first impression was it's a city rich with culture and you find a mix of local and international flavor.
Allahabas has very little to offer the tourist. We were there for Kumbh Mela. Apart from that the only real attractive is the home of the Nehru family.
Historical city located at the merging point of two great rivers of India, the Ganges and the Yamuna