(Left) Oct. 31, 1977: Louis Seltvitella, as C3P0, and Jim Webb as Darth Vader walk through Harvard Square in Cambridge. (Right) Oct. 31, 1983: Errol Alim Jr., 3, headed up the steps of a house in Dorchester while trick-or-treating in a Zorro costume made by his parents.

John Blanding/Globe Staff/Globe Staff