That’s the old Girls’ High School on Nostrand Avenue in Brooklyn, constructed in 1886. Academically, it has a slightly convoluted history, but it was the first public high school constructed in greater New York, in the then-independent city of Brooklyn. It was going to serve both boys and girls but the growing school population required more space, so this building was used for girls and a separate Boys’ High School built nearby. There are, today, around 150 high schools in Brooklyn, and the Boys’ and Girls’ schools merged in 1975.
The happiest part of the story is that the building is still in use as a school, as an adult education center run by the city. Sometimes the best adaptive reuse requires little adaptation.