The Indian Ocean tsunami occurred on December 26, 2004, following a massive undersea earthquake off the coast of Sumatra, Indonesia. The earthquake, measuring 9.1 on the Richter scale, triggered a series of powerful waves that affected several countries bordering the Indian Ocean, including Thailand, Sri Lanka, and India. The tsunami caused widespread devastation, resulting in over 230,000 fatalities and displacing millions. It was one of the deadliest natural disasters in history, leading to significant humanitarian efforts and changes in tsunami warning systems across the region to better prepare for future events.