On July 2, 1921, one of our photographers captured this group of 10,000 men in straw hats gathered in Times Square to listen to updates on a prize fight. In those days, straw hats were a go-to summertime accessory. But wearing one after the somewhat arbitrary date of Sept. 15 was considered a fashion faux-pas.

"Beware! The 15th falls on Tuesday next and after that mystic notch in the calendar has been passed men may continue to wear straw hats at their peril," The New York Times Magazine wrote in 1925. Presidents were not exempt from the rule either. When President Coolidge wore a straw hat on Sept. 19 of that year, the fashion crime made the front page. "President Coolidge plainly intends to ignore the unwritten law banning the wearing of straw hats after Sept. 15," The Times reported. "Yesterday, which was close and hot, he wore his straw hat on a late afternoon stroll, and today he again appeared in the tabooed headgear."

The issue reached a peak three years earlier, though, during New York City's Straw Hat Riot of 1922. "Gangs of young hoodlums ran riot in various parts of the city last night, smashing unseasonable straw hats, and trampling them in the street," The Times reported. The next day, the courts issued a warning: "The inalienable right of a man to wear a straw hat in a snowstorm, if he desires, is to be upheld in this city by both police and the Magistrates."