Where Iran’s Nuclear Program Goes From Here

Deep beneath the Zagros Mountains in central Iran, in a labyrinth of fortified tunnels outside the city of Natanz, centrifuges spun at speeds too fast for the eye to track. The cascade of machines, arranged in long halls and shielded by concrete and steel, have been central to Iran’s most sensitive nuclear work, and, until recently, largely immune to airstrikes. But this month Israeli warplanes penetrated Iranian airspace and struck multiple nuclear sites, including underground facilities thought to be untouchable.