Five kilowatts. That was the modest output when Soviet scientists at the Obninsk Nuclear Power Plant powered up Reactor AM-1 on June 27, 1954, and fed the first nuclear-generated electricity ever into a public grid. Located in Obninsk, a closed scientific city southwest of Moscow, the plant was the crowning achievement of a crash program led by physicist Igor Kurchatov and the broader Soviet atomic establishment. The graphite-moderated, water-cooled reactor reached just five megawatts of thermal capacity, tiny by modern standards, but it proved the concept that splitting atoms could light homes, not just level cities. Western observers, still locked in Cold War suspicion, scrambled to understand what the Soviets had accomplished. The reactor ran without pause for 48 years before finally shutting down in 2002. Today, roughly 400 nuclear power plants generate about ten percent of the world's electricity, and every one of them traces its lineage to the quiet hum that began in Obninsk on a June afternoon in 1954.