The photo commemorates the death of former President Madero. There is an obvious amount of reverence being given to Madero as crowds of people have lined up to see his funeral procession out of the prison. It appears from the photograph that there were several guards charged with keeping the coffin’s path clear and also guards in charge of escorting the coffin, this then leads us to believe that Madero’s body needed protection from those that sought to desecrate it. Along with the escort guards are several well-dressed gentlemen that appear to hold some kind of power themselves. This then begs the question, “who was Madero to command this respect?” and then from investigation it is found that Madero was a fighter for democracy and Mexican independence that was instrumental in removing President Diaz from his extended stay in office. From this even of dethronement, Madero grew in favor among the citizens that sought equality in rights, and it is clear that these people did not forget the actions taken by their former leader and revolutionary.
http://digitalcollections.smu.edu/cdm/singleitem/collection/mex/id/137/rec/37