People with AIDS Plaza

I'm walking along Broadway next to City Hall Park and I was looking up at some architectural details of another building when I noticed this street sign that said "People with AIDS Plaza". I'm on the sidewalk,, there is no plaza... as I walked around the park there were a few other oddly named street signs hanging from the cool street lamps. There is the Steve Flanders Square and Susan B. Anthony & Elizabeth Cody Stanton Corner. On the other side of City Hall Park on Park Row there is another sign that reads "People with AIDS Plaza", the two have no connection that I can figure out. I'm not sure if there are two Plazas or if there is something in between within the park. I couldn't find any plaque or stone or planting within the Park.

After a search on the web and on the nyc.gov website, I found no reference. People have written about this sign,, but there is nothing official I could find as to its origin. This will be a mystery.