What 2019 folk horror film directed by Ari Aster follows a group of American friends who travel to a remote Swedish commune for a summer festival, only to find themselves entangled in a pagan cult's rituals?

The 2019 folk horror film you're thinking of is "Midsommar (Review)," directed by Ari Aster. This unsettling movie centers on Dani, played by Florence Pugh, an American graduate student grappling with profound personal trauma. Her already strained relationship with her boyfriend, Christian, is further tested when they, along with his anthropology friends, accept an invitation to a remote Swedish commune for a once-in-a-lifetime midsummer festival.

Upon their arrival at the idyllic-looking Hårga commune, bathed in perpetual daylight, the group initially experiences what seems like a picturesque cultural immersion. However, the seemingly harmonious celebrations soon take a sinister turn, revealing the commune's true nature. The friends (Review) find themselves increasingly disturbed and entangled in the Hårga's ancient, violent pagan rituals, which involve ritualistic suicides and sacrifices.

"Midsommar" is renowned for its unique approach to horror, eschewing traditional jump scares and darkness for a bright, sun-drenched, yet deeply disturbing atmosphere. The film deftly explores themes of grief, trauma, toxic relationships, and the search for belonging, all while showcasing a stark cultural clash between the American visitors and the isolated, ancient traditions of the Hårga. Dani's journey through the festival becomes a psychological unraveling, as she is forced to confront her emotional vulnerabilities amidst the escalating horrors.