I think everyone's sick of "Every [this or that] in New York" projects, where artists present a multitude of items of some type, believing that sheer numbers will give the project weight. The projects usually feel like "What I did on my summer vacation" or "At least one of these has to be good, right?"
But if I had all the time in the world, I'd do it too, and take pictures down every open grate, manhole and stairwell I pass.
Then, after digitally replacing all the buildings above ground with grassland, I'd put the best pictures together to make an inhabited sidewalk a few miles long. I've seen some interesting stuff down there, including trees.