Directed by Patricio Guzmán—the man behind the monumental three-part documentary The Battle of Chile—Nostalgia for the Light is a cinematic poem about the history of Chile and the history of the universe. The point where these two histories meet is one of the driest and most cloudless places on earth, the Atacama Desert in northern Chile. The desert is so severe, so unearthly, that it is used to test machines and instruments for planned trips to Mars. Despite the unwelcoming, Mars-like terrain, the desert hosts a community of telescopes that look into the depths of space and time (the history of the universe), and a group of women who search the desert for loved ones who were murdered by the dictator Augusto Pinochet (the history of the country). In the mid-1970s, Pinochet set up a death camp in an abandoned saltpeter mine.

The reason the mine was abandoned can be found in the invention of the Haber-Bosch process, which industrialized the production of nitrogen. The reason the Germans developed this process in the first place is because they did not have access to the saltpeter mines in Chile (they were controlled by the British). One theory has it that the Germans rapidly industrialized nitrogen production for military reasons. But the process that was used for the production of German explosives during the first great European war of the 20th century is also the same process that's responsible for the fact that seven billion humans live on the world at this time. Without artificial access to nitrogen, there would not be enough of the vital nutrient to sustain this enormous human population.

The documentary, however, barely mentions any of this. Nostalgia—which is beautiful, dreamy, and slow—is mostly about the dead in the desert, the women who are looking for them, and the astronomers who are watching the wandering stars. Northwest Film Forum, Fri 7, 9 pm, Sat 9 pm, Sun-Tues 7, 9 pm.