This church, the Santuario Nuestra Señora de Balvanera, commonly known as the Santuario de San Expedito is one of the oldest churches in the city with history dating back to 1797.
It was built for the Virgen de Valvanera, the V not being a mistake but the name of a valley in La Rioja, Spain. The place of worship was built on lands donated by González Varela, known as Miserere (the loved and generous neighbor mentioned earlier).
Today this is one of the most beautiful churches in Buenos Aires, definitely take time to step inside past the vendors hawking San Expedito merch.
You can read more about the history of this church here.