I flew into New York City two weeks after the Twin Towers were destroyed. Driving into Manhattan from the airport, I could see, illuminated by huge lights, dust still rising from the debris.
That next morning: I saw strangers in the subway talking to one another. New Yorkers didn’t seem to do that before. A city I loved so much gave me and everybody else in the world even more to love.
This was one of thousands and thousands of memorials placed throughout the city. It was in front of the Washington Square Park Arch, through which, standing on Fifth Avenue, before September 11, 2001, one would see the Twin Towers.
basil.CA 
On behalf of NYC (and Berkeley, CA), thanks Bob.