[3][4] In Nazi concentration camps, each prisoner was required to wear a downward-pointing, equilateral triangular cloth badge on their chest, the color of which identified the stated reason for their imprisonment.
[16] In the 1970s, newly active Australian, European and North American queer liberation advocates began to use the pink triangle to raise awareness of its use in Nazi Germany.
[17] In 1972, gay concentration camp survivor Heinz Heger's memoir Die Männer mit dem rosa Winkel (The Men with the Pink Triangle) brought it to greater public attention.
[19] Publications such as San Francisco's Gay Sunshine and Toronto's The Body Politic promoted the pink triangle as a memorial to those who had faced persecution and oppression.
The biangles symbol was designed by artist Liz Nania as she co-organized a bisexual contingent for the Second National March on Washington for Lesbian and Gay Rights in 1987.
[24][25] Taking a more militant tone, the AIDS Coalition to Unleash Power (ACT UP) was formed by six gay activists in New York City in 1987, and to draw attention to the disease's disproportionate impact on gay and bisexual men, and the apparent role of "genocidal" queer-antagonism in slowing progress on medical research,[26] adopted an upward-pointing pink triangle on a black field along with the slogan "SILENCE = DEATH" as its logo.
[citation needed] In the 1990s, a pink triangle enclosed in a green circle came to be commonly used as a symbol identifying "safe spaces" for LGBTQ+ people at work or in school.
In 1993, historian Klaus Müller argued that "the pink triangles of the concentration camps became an international symbol of gay and lesbian pride because so few of us are haunted by concrete memories of those who were forced to wear them.
In 1980 a jury chose the pink triangle design for the Homomonument in Amsterdam, to memorialize gay and bisexual men killed in the Holocaust (and also victims of anti-gay violence generally).