Dude... it's New York City... maybe the most diverse city (top 3 anyway) in the most diverse country in the world... I'm almost surprised there's not more. I used to work at an industrial laundry in Manassas, Virginia where nearly 60 different nationalities were represented among our staff.
And, also, the four weapons used to target the WTC and Pentagon that day were four large commercial aircraft full of passengers who had just taken off from international airports, so... there's that, too.
There were 19 different nationalities among those killed by the July '05 bombings in London which had 55 victims compared to the nearly 3,000 on 9/11. These are global cities.