It ranked among the worst natural disasters in human history - the most deadly tsunami on record, and among the top ten disasters of any kind since 1900. The Indian Ocean tsunami of December 26, 2004 also served as a wake-up call for people all around the rim of that sea, alerting them that tsunamis can strike anywhere.
The common name "tsunami" hints at the fact that most of these events strike in the ever-turbulent Pacific Ocean. We use a Japanese word for it in English, because Japan has long dealt with the phenomenon of the sea drawing back suddenly, and then hurling itself at the land. Unfortunately, though, it was the unprepared people of Indonesia, Thailand, Sri Lanka, and even Somalia who bore brunt of the 2004 event.
Photo of damage in Aceh, Indonesia by Patrick M. Bonafede, US Navy via Getty Images.