The Wicker Man (1973)

I think we can all agree that imperialism is pretty bad. Early christian missionaries demolished indigenous cultures and, in some cases, eradicated native populations in the name of their god, their empire of heaven. There are things completely lost to us now, religious rites and fetishes, objects of both anthropological and social interest that we can never get back.
The Wicker Man is a film essentially about the danger of religious imperialism. When celibate christian police officer Howie (Edward Woodward) goes to an island off the coast of Scotland to investigate a missing person, he stumbles into a conspiracy. The towns people all deny the existence of the missing girl, including her own mother. Soon, he finds himself wrapped up in pagan tradition and worship, all under the watchful eye of the island's lord, played by Christopher Lee. As Howie attempts to criminalize their worship, he finds a depth of "depravity" he could never have imagined.
It is a story of an incredibly naive man, a man raised in an insanely insular fashion, who lives his life completely closed off to thought, trying to destroy the religious beliefs of a small community. When we learn the recontextualizing twist, that Rowan was a macguffin, Howie's reaction removes all sympathy. He switches from biological justification for his crusade, to religious justification so quickly, making his motivation to simply destroy that which threatens him. Perhaps Howie deserves his fate. As Lord Summerisle says, he can die a martyr's death, in his christianity as well as in the island's mythology.
The Wicker Man is a tremendous film. As the presence of Christopher Lee implies, it is a 70s British horror film, with all the baggage that entails. However, its almost entirely well-acted, the script is a work of genius, and the direction shows glimpses of brilliance. Its absolute a film worth watching, especially with an ideological eye.