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.

People are gathering in prayer and visiting mass graves in Indonesia’s Aceh province to mark 20 years since the massive Indian Ocean tsunami, one of modern history’s worst natural disasters

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.

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

People have started gathering in prayer and are visiting mass graves in Indonesia’s Aceh province to mark 20 years since the massive Indian Ocean tsunami, one of modern history’s worst natural disaste

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

Indian Ocean tsunami commemorated its 20th anniversary. Countries such as India, Thailand, Indonesia, and Sri Lanka held memorial services, dispersing flowers into the sea and lighting candles in remembrance of the victims.

A candlelight vigil was held on Thursday in the Thai village of Ban Nam Khem to mark 20 years since the massive Indian Ocean tsunami hit the region in one of modern history’s worst natural disasters.