There’s more to the rainbow flag’s history than we knew.

Gilbert Baker, Lynn Segerblom, Robert Guttman and another volunteer, pictured in 1978, hold up one of the original rainbow flags for the Gay Freedom Day Parade in San Francisco. (James McNamara)

It was the summer of 1978, and the Gay Community Center in San Francisco swarmed with dozens of young hippies flitting between ironing boards, sewing machines and trash cans filled with colorful dye.

They had been tasked with making two enormous flags to fly above the city’s Gay Freedom Day Parade…