A weather front rolls in from the horizon, storm clouds darken the sky, and (at least 1.3 billion times a year) lightning strikes. Last month, the National Weather Service promoted their Lightning Safety Week, with information designed to call attention to safe practices, helping people avoid lightning strikes which kill an average of 100 people every year. While the exact nature of the initial formation of lightning remains a subject of debate, what is known is that lightning strikes are caused by electrical imbalances present in the clouds. Those imbalances correct themselves suddenly, with an often spectacular light show - which I've tried to show here, with a handful of recent photographs of lightning from around the world. ( 26 photos total