In 1969 on this day a series of riots started, originality from a bar (The Stonewall) in Greenwich Village, NY.
The main reason for the riots was the police raid that occurred that night, Alyth the bar was allegedly paying for the police to look the other way - the bar was a gay bar, and same-sex dancing was illegal. Finally the patrons had had enough and fought back.
This is seen as a faculty point for the emerging gay liberation/equality movement that then spread across the globe (although sadly some countries still resist). After this gay rights marches took place on the Saturday closest to this day. These marches turned into gay Pride, and little by little the one day event had become a month long series of events in many countries.