Inscription:

On April 21, 1966, members of the Mattachine Society, a pioneering gay rights organization, challenged a regulation that prohibited bars from serving LGBT people by staging a "Sip-In" at Julius', a bar with a large gay clientele.

With reporters and a photographer in tow, the activists announced that they were homosexuals, asked to be served, and were refused. This early gay rights action and the attendant publicity helped to raise awareness of widespread anti-LGBT discrimination and harassment. Julius' was listed on the National Register of Historic Places in 2016.

https://www.hmdb.org/m.asp?m=198561