Well, the first in NYC, unless I’m reading this wrong

On Saturday, June 27, 1970, marches to mark the first anniversary of Stonewall were held in Chicago and San Francisco, followed on Sunday, June 28, 1970, by the Christopher Street Liberation Day Parade in New York and the Christopher Street West Association Parade in Los Angeles; the four gatherings were the first Pride parades in United States history.

And that, children, is the reason why all computers think of 1970 as the first year time existed. I am writing this 1748793147 seconds after 1/1/1970.