The environmental idealism and counterculture roots of 1991’s grand Biosphere 2 experiment—where a group of eight researchers locked themselves into a purpose-built Arizona biodome for two years—are revealed in Matt Wolf’s absorbing new documentary, drawn from 600 hours of footage shot or collected by the participants themselves. San Francisco avant-garde theater troupes, homemade boats that sailed from Oakland across the world, Texas billionaires, New Mexico communes, Harvard MBAs turned actors turned entrepreneurs turned conservationists: all of these figure in the tale of the biodome in the desert outside Tucson, where environmental activism, scientific study, and artistic creativity slowly disintegrated under pressure from business demands, deepening interpersonal paranoia, and growing media disdain. As this film was being made, the idea of a group of people confining themselves in a closed environment seemed like a strange sci-fi fantasy; now, thanks to COVID-19, “we are all living like biospherians, and we too will reenter a new world,” Wolf writes. The question of what kind of world we will reemerge into has only become more pressing.