La Guardia, the ,participant, float show of support for World War II was part military parade and part civilian homefront procession. An estimated 2,, fervent spectators thronging the streets cheered them on, all the way up Fifth Avenue, from Washington Square Park to 79th Street. But by all accounts, not every patriot was welcome. Top: Air Raid Instructions poster. Grant MacKenzie, who was killed in a bomber crash while doing important research work in Otology.