This year marks 20 years since the devastating Indian Ocean Tsunami that left more than 220,000 people dead or missing from Southeast Asia to East Africa. A commemorative event was held in Thailand to raise awareness of the importance of preparing for disasters.

About 100 people attended the symposium on Thursday in Bangkok. People in a panel discussion highlighted the need to expand early warning systems for all coastal areas of the world and make them more disaster-resilient.

The 2004 tsunami was triggered by a massive earthquake off Indonesia's Sumatra island on December 26.

Thailand was one of the countries badly hit, with more than 8,000 people killed or missing in southern provinces. There was no warning for tourists and residents. The country has since set up warning systems to prepare for such disasters in the future.