This post was originally published on Oct 27, 2015.The location of Pandora's Box, one of New York City's most elite S&M dungeons, isn't a secret: The Manhattan facility advertises its address on its website . If you aren't a staff member or client, however, access is tricky — one of the reasons that Pandora's Box , documentary photographer Susan Meiselas' 1995 photo series of intimate encounters in the dungeon, is so powerful.Widely known for her work documenting human rights issues in Latin America (she took the iconic " Molotov Man " photograph, which came to symbolize the Sandinista overthrow of Nicaragua's Somoza dictatorship), Meiselas recalls that Pandora's Box attracted an audience that may not otherwise have considered BDSM culture. "There were people who knew my work on human rights and mass graves in the '80s, who didn’t understand this," she says. "When I began to talk about this question of what is really going on between these two people in this space, the giving and the desire for pain, the people who knew my work would not have pursued it themselves, but they found it more interesting."To mark the 20th anniversary of the photo series, we spoke with Meiselas about her immersion in a community that's not often open to outsiders — as well as her take on how attitudes toward sex and BDSM have shifted. "Of course it's a secret world," she says of Pandora's Box. "Of course it's also true that many of the men wear masks, so their identities were protected; that’s why my relationship with the dominatrix was key. It was key that they wanted me there."Thanks to the trust she established with her subjects, Meiselas' photos capture dominatrices and clients performing "not so much for my camera, but for each other," she says. Click through for 19 striking images of this performative exchange, alongside reflections from Meiselas.