On December 26, 2004, a massive earthquake off the coast of Sumatra triggered one of the most devastating tsunamis in recorded history. The waves affected multiple countries along the Indian Ocean, including Thailand, Sri Lanka, India, and Indonesia, killing over 230,000 people. Entire coastal communities were swept away, and millions of people were left homeless. The disaster led to one of the largest international humanitarian responses in history. The tsunami also spurred improvements in tsunami detection systems and international disaster coordination.