The 2004 Indian Ocean Tsunami was a devastating natural disaster that occurred on December 26, 2004. Triggered by a massive undersea earthquake measuring 9.1 to 9.3 off the coast of Sumatra, Indonesia, the tsunami affected several countries bordering the Indian Ocean, including Thailand, Sri Lanka, India, and Maldives. The waves reached heights of up to 30 meters (100 feet) and traveled across the ocean at high speeds, causing widespread destruction. It is estimated that over 230,000 people lost their lives, making it one of the deadliest tsunamis in history. The disaster prompted a global humanitarian response and raised awareness about tsunami preparedness.