The morning after Christmas, the sea pulled back further than anyone had seen, and people walked out onto the exposed sand before they understood what it meant. Then it came back all at once, across fourteen countries, before most of the coast had any warning system at all. A magnitude 9.1 earthquake off Sumatra triggered waves that reached Sri Lanka and even the coast of Africa within hours. The death toll — well over two hundred thousand people — took weeks to become real, climbing every time the news came on. What stayed with people wasn't just the wave, it was how many strangers, thousands of miles away, sent help within days. Some disasters make the whole world briefly act like one place.