Gilbert Baker first created the Rainbow Flag with a collective in 1978.  He refused to trademark it, seeing the flag as a symbol that was for the LGBT community.

To commemorate the 20th anniversary of Harvey Milk's election to the SF Board of Supervisors, Gilbert found an unused flagpole and convinced the Board to install it on the grounds of Harvey Milk Plaza.  It was dedicated to Milk on Nov. 8, 1997 and has flown Gilbert's large rainbow flag ever since.