I believe that this is the: Iglesia de Nuestra Señora de Belén in the San Telmo neighborhood of Buenos Aires. It's on Humberto Primo, just off Defensa with the Prison Museum adjoining.
I don't know the city well enough to be absolutely sure. I believe I was standing in front of the church when I took: http://www.pbase.com/venicepix/image/51797018 and then either John or I turned around and looked up and shot this...