In late January 2018, Israeli spies from Mossad stole 100,000 documents from a warehouse in a southern suburb of Iran’s capital, Tehran, and exfiltrated the materials back to Tel Aviv. Among this cache of papers, CDs, and computer files, Prime Minister Benjamin Netanyahu’s government unearthed the history of the Islamic Republic’s secret nuclear weapons program. It was code-named the AMAD Plan.

Israeli intelligence analysts who combed through the materials that winter learned about the importance of Iran’s overt uranium enrichment facilities to this bomb-making program, which were stationed in cities and towns like Natanz, Isfahan, and Fordow. But they also discovered that there were dozens of other undeclared nuclear sites that crisscrossed Iran’s 636,000 square miles and housed sensitive equipment and fissile material. The Israelis pinpointed the scientists, military officers, and bureaucratic offices driving the activities of the AMAD program and its related Iranian entities.