Electricity (practical, 1879)

Thomas Edison's practical incandescent light bulb in 1879 didn't just extend daylight — it ignited the Second Industrial Revolution, enabling motors, refrigeration, communication, and computing. By 2023, global electricity generation reached 29,000 terawatt-hours, powering hospitals and data centers alike. It is 100% essential to modern civilization, driving a 40% reduction in mortality rates since 1900 through electric lighting, refrigeration, and medical equipment, and its 30% lower average cost per kilowatt-hour than gas lighting transformed urban life.