On 26th of December 2004 an undersea earthquake triggered a tsunami which struck  communities along the coasts of the Indian Ocean, It killed an estimated 227,898 people in 14 countries.

The earthquake was the third-largest ever recorded, the largest in the 21st century and had the longest duration of faulting ever observed, between eight and ten minutes. It caused the planet to vibrate as much as 10 mm (0.4 in), and also remotely triggered earthquakes as far away as Alaska. Its epicentre was between Simeulue and mainland Sumatra. The plight of the affected people and countries prompted a worldwide humanitarian response, with donations totalling more than US$14 billion.

Wikipedia

You can find out what has happened since then to the communities affected by following this link: The Conversation

Special Report: Boxing Day Tsunami Anniversary