Jim, The most famous Day in the history of the FFL is Camerone Day, 30 APRIL, which remembers the battle in Mexico on that day in
1863. Wiki tells the tale better than I can. It is the heart and soul of the Legion, and should be the stating point for your research into the FFL in the Americas.
https://en.wikipedia.org/wiki/Battle_of_Camar%C3%B3n