Two decades after a devastating earthquake and tsunami struck Indonesia, some survivors are rebuilding their lives in the same location, while others are too traumatized to return.

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 triggered tsunami waves that killed some 230,000 people across a dozen countries.