Most of us think of the Stonewall riots as the birth of the gay rights movement. But on July 4th, 1965—four years earlier—40 brave picketers carried placards calling for equality in front of Philadelphia's Independence Hall.

Their brave act of defiance will be commemorated in a reenactment this July 4, as part of the National LGBT 50th Anniversary Ceremony.

Forty activists will carry placards with identical messages from the first Annual Reminder, as the historic event has become known.

Led by Frank Kameny and Barbara Gittings, the 1965 demonstration wasn't just groundbreaking—it started a tradition of Annual Reminders outside Independence Hall from 1965 to 1969.

They marked the first time activists from different cities—Philly, New York and Washington, DC—came together, and the first time gays and lesbians demanded equality, not just compassion or tolerance.

"In the early 1960s, there were only about 200 gay activists in the nation," Said Malcolm Lazin, chair of the  National LGBT 50th Anniversary Celebration. "When 40 picketed at Independence Hall on July 4th, 1965, it was the largest demonstration for gay equality in world history."

Hosted by Wanda Sykes, the National LGBT 50th Anniversary Ceremony will also feature speakers, musical performances, and tributes to Kameny and Gittings, considered the father and mother of the modern gay rights movement.

The two are also the subject of a documentary, The Gay Pioneers, screening this weekend.

Other events include a live concert, an interfaith service with Episcopal Bishop Gene Robinson, a luncheon with Judy Shepard and Edie Windsor, and a wreath-laying ceremony with SCOTUS plaintiff James Obergefell at the Gay Pioneers Historical Marker.