Have you ever been to New York City? It has the largest population of people in one city!
Not really, but what is the population size
In 2016 it was estimated to have over 8,537,673 people, so that number could be much more in such a densely populated area.
OK, what a large city. What is their cultural value?
New York City has such a diverse population that contributes to the world's financial, cultural, and media outlets. 
Wow, that is cool. Is like their system of education is good too
Yes, and immigration is very key in the New York area considering that over 800 languages are spoken in New York. 
800 languages? That is cool, do u know how to speak any?