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

The powerful 9.1-magnitude earthquake off the coast of the Indonesian island of Sumatra, triggered a tsunami that killed around 230,000 people across a dozen countries.

The earthquake and tsunami claimed the lives of over 200,000 people, the deadliest natural disaster of the 21st century.

One of the deadliest natural disasters in modern history, the 2004 Indian Ocean tsunami marks its 20th anniversary on Dec. 26

Survivors and families of victims visited mass graves, lit candles and comforted one another across Southeast and South Asia in ceremonies to mark the disaster that killed some 230,000 people.

People gathered in India and Sri Lanka on Thursday to mark 20 years since the Indian Ocean tsunami struck , killing thousands of people.