A crowd by an arched building

This medium format black & white picture comes from a series of 6x4.5 negatives I acquired which all seem to show views of Mexico in the 1930s. The scene shows a crowd of people in front of an arched building who are either listening to someone or possibly waiting to listen to someone. I can just make out an oval display at the front which could be some sort of religious display so this could be a religious event.