About 20 minutes into Dog Day Afternoon, I feared I had made a grave mistake. My eyes drifted to the clock as I counted down the minutes, carefully tracking how much longer I’d need to wait for the movie to be over. This initial reaction shocked and disappointed me considering Dog Day Afternoon has hovered near the top of my “to watch” list for years.

But another 90 minutes or so later, I suddenly understood what I’d been missing. Over the course of its two hours, Sidney Lumet’s drama based on the true-life story of a Brooklyn bank robbery transforms fact into a well-crafted exploration of the explosive political clime of the 1970s. Pre-marriage equality, pre-AIDS, and pre-Harvey Milk, Dog Day puts a queer character at the center of the story during a period of time where the LGBTQ community was largely invisible to the straight mainstream.

Thankfully, this was a fact that came as a complete surprise to me allowing its reveal to be a delight. I watched Sonny (Al Pacino) bumble his way through what seems to be his first armed robbery, eventually demanding to speak with his wife. Lumet then starts intercutting scenes of a woman and her two children learning about Sonny’s predicament with shock and horror. But when the cops announce they’ve finally located his wife, we don’t see the woman from those scenes. We see Leon (Chris Sarandon). Nails painted, wrapped in a bathrobe, Leon plays the part of the frightened and disappointed wife.

Seeing Leon shocked me, which I think it might have even if I’d already known the rest of the details about this true tale—that the whole point of the heist was to get the money to pay for his gender-reassignment surgery. I say it shocked me not because I think there’s anything shocking about a transgender character, especially not in a new age where movies like Tangerine and actresses like Laverne Cox can get their well-deserved due. But because for a film made in 1975, it’s remarkably sensitive to Leon’s plight.

We see cops and some people in the crowds bristle at Leon, laughing at him (and I call him “him” as his female identity is never explored nor named over the course of the movie) and even mocking him. Yet the jibes are never gratuitous and camera stays focused on Leon’s reactions, never allowing those that don’t understand him to overshadow him. Lumet frames Leon in such a way that it’s his relationship with Sonny that takes centerstage, not his gender identity. While I hesitate to heap too much praise upon it (I’m not sure how a transgender audience would react to Leon today—he’s played by a straight cis actor and the script refuses to acknowledge his female identity), it’s undeniably impressive.

Even the subtle exploration of the larger gay rights movement was surprising and refreshing. As the crowd grows around the bank, we hear chants of, “Out of the closet, into the streets!” which served as one of the main refrains of LGBTQ protests and marches. The camera pans across the diverse array of faces, each of which is rooting for Sonny, even if they’re not sure why.

I expected a heist movie, and to be sure that’s what Dog Day Afternoon is. It follows all of the beats you’d expect, but the way it seamlessly and effortlessly contextualizes the events of this one day within the larger framework of American counterculture, a post-Vietnam world, and gay rights is absolutely stunning.