Peeking up from the sidewalk concrete, this is one of a score or so of metal loops on one Morningside Heights corner. Most are along the side street. Today the ground floor of the adjoining property, one of the neighborhood's ubiquitous five-floor walkups, is occupied by a branch of a nationally known bank, but years ago (perhaps decades ago is closer to the truth) it was home to a family-run greengrocer. A Korean family, I think. Loops like this helped anchor awnings, which extended out and down to cover the stoopline display and shielded produce and flowers from the afternoon sun.
Morningside Heights, Manhattan