In June 1969, members of the LGBT community responded to police brutality aimed at LGBT people at a gay bar in New York City. This refusal to sit silently in the face of discriminatory abuse helped inspire the LGBT community and their allies across the United States, giving birth to the modern LGBT rights movement. This event is commemorated annually every June, known as Pride month, in U.S. and international communities with festivals and marches.
Presidential Proclamation-LGBT Pride Month: http://m.whitehouse.gov/the-press-office/presidential-proclamation-lesbian-gay-bisexual-and-transgender-pride-month