Survivors and mourners gathered at mass graves in Indonesia, Thailand and other places along the Indian Ocean that were devastated by the 2004 tsunami — the deadliest in the world.

Christmas in 2004, a 9.1 magnitude earthquake under the Indian Ocean triggered tsunami waves that killed some 230,000 people across a dozen countries.

The Asian tsunami that crashed into coastal communities around the Indian Ocean on Dec. 26, 2004, is this century’s deadliest natural disaster so far.