On the fateful morning of December 26, 2004, more than 2,27,000 people in South Asia were killed by a tsunami triggered by a powerful undersea earthquake. Seventeen years on, here's a look at some facts about one of the deadliest disasters in modern history.

What caused it?
The Sumatra-Andaman earthquake of 9.1 magnitude, the third-most powerful quake since 1900, caused a 100-foot-high wave and hit shorelines all along the Indian Ocean, reaching 14 countries, including Indonesia, Sri Lanka, India, Maldives and Thailand - without any warning. It struck 150 miles from the coast of Sumatra island in Indonesia, and 31 miles below the ocean floor. The earthquake itself was caused by the subduction of the Indo-Australian plate under the Eurasian plate.