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.

In Thailand, people gathered at a memorial ceremony in Ban Nam Khem, a small fishing village in Phang Nga province that bore the brunt of the devastating wave in the country. The tsunami claimed the lives of over 8,000 people in Thailand. Many remain missing and nearly 400 bodies are unclaimed to this day.