1971: Seven lesbians, including Barbara Gittings, break new ground on U.S. Television when they appear on The David Susskind Show.

1972: The United States Supreme Court issues its ruling in Baker v. Nelson, in which the plaintiffs sought to have Minnesota’s restriction of marriage to different-sex couples declared unconstitutional. The Court dismisses the case “for want of a substantial federal question”

1973: The Toronto city council passes a resolution banning discrimination on the basis of sexual orientation in civic hiring.

1987: 2,000 gay and lesbian couples exchange vows in a mass wedding held on the steps of the I.R.S. building in Washington, DC.

1995: The United States Supreme Court hears oral arguments in Romer v. Evans, the case that would eventually overturn Colorado’s Amendment 2, which banned gay rights laws in the state.

1996: The Argentinian city of Buenos Aires enacts legislation banning discrimination based on sexual orientation and repealing laws that allowed police to arrest lesbians and gay men and hold them without charge for 24 hours.

2008: Connecticut overturns a state ban on same-sex marriage and becomes the third U.S. state to legalize marriage for same-sex couples, following Massachusetts and California.