In Parasite, Bong Joon Ho’s black comedy about class divisions in South Korea, there are two main settings. The first is the home of the Kim family—a semi-basement apartment with a stink bug infestation, where you can only get Wi-Fi in the bathroom and the alley view is often infiltrated by an unwieldy, urinating drunkard. The second is that of the wealthy Parks. The mansion is a master class in Korean modernism, made by a “fancy architect” and filled with “fancy art,” with a manicured green lawn and hedges to keep the world—and its unwieldy drunkards—out. Bong references an army of societal differences throughout the film (the Kims smell different than the Parks, etc.), but none are as symbolic as their homes.

The homes are just as much characters as Da-Song, Mr. Kim, or “Jessica, Only Child, Illinois, Chicago.” The Parks’ house is even, for a time, the love interest for all involved: the Kims covet it; former housekeeper Moon-gwang pines for it; and the Parks see it as their prize possession where, to borrow a line from Fitzgerald, they retreat “back into their money or their vast carelessness, or whatever it was that kept them together, and let other people clean up the mess they had made.” But the house has secrets that destroy everyone. The palace, as it turns out, was a prison this whole time.

At first, the Kim house is an antagonist that the family must escape. Its most villainous moment—spoiler alert—comes when it floods, destroying their possessions and casting them into the streets. But when the family returns at the end of the film, back where they started, the viewer breathes a sigh of relief. And, with how she attentively polishes the furniture, it seems Mrs. Kim does too.

The perils that both houses thrust upon their inhabitants is, in part, what makes Parasite so sinister. “Houses usually should feel very mundane, cozy, and comfortable. And when that is threatened, that is when we feel the most fear,” the film’s set designer, Lee Ha Jun, told Architectural Digest.

There’s this concept called hostile architecture—or design that inflicts discomfort. It’s usually associated with public, urban spaces. Cities use metal spikes on public walls, dividers on benches, or bike racks under bridges to discourage homeless loitering, for example. Landlords evoke it when wanting to push out “undesirable” tenants in a process known as constructive eviction: the act of rendering a home unlivable by refusing to fix things like broken heaters so a tenant is forced to leave. The Kim house, Bong shows, inherently embodies this: Its partial subterranean architecture is inhospitable to humans; its dilapidated state only allows the stink bugs to thrive.