From the NY Times:
Over the past 17 years, thousands of pieces of human remains dating back to the 18th century have been unearthed in the course of construction projects in and around City Hall.
In a quiet ceremony on Sunday afternoon presided over by Christian, Jewish and Islamic clerics, city officials reburied them and unveiled a marker in their remembrance, near a grove of ginkgo trees at the northeast corner of City Hall Park.
The burials were associated with an almshouse built in 1736 where City Hall now stands, two prisons, a barracks for British soldiers and the African Burial Ground.
“Some of the earliest New Yorkers were laid to rest on and near this site,” the landmarks preservation commissioner, Robert B. Tierney, said at the ceremony. “It is my hope that this marker might compel anyone who comes upon it to stop, read it, and maybe consider for a moment the New Yorkers who were a part of a settlement that evolved into the great city New York is today.”
Let's not dwell on the other locations of graves that have been disturbed in order to accommodate development. Rarely are the remains ever reburied and the dead commemorated with plaques. (It tends to be bad for real estate sales.)