BANDA ACEH, Indonesia: People started gathering in prayer on Thursday and visiting the 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.

Many openly wept as they placed flowers at a mass grave in Ulee Lheue village where more than 14,000 unidentified and unclaimed tsunami victims are buried.

It is one of several mass graves in Banda Aceh, the capital of Indonesia’s northernmost province. It was one of the areas worst-hit by the earthquake and tsunami, along with the district of Aceh Besar.

“We miss them and we still don’t know where they are. All we know is that every year we visit the mass grave in Ulee Lhue and Siron,” said Muhamad Amirudin, 54, who lost two of his children 20 years ago and has never found their bodies.

“This life is only temporary, so we do our best to be useful to others,” Amirudin, visiting the grave with his wife, said.

A powerful 9.1-magnitude earthquake off the coast of the Indonesian island of Sumatra on Dec. 26, 2004, triggered a tsunami that killed around 230,000 people across a dozen countries, reaching as far as East Africa.

Some 1.7 million people were displaced, mostly in the four worst-affected countries: Indonesia, Sri Lanka, India and Thailand.

More than 170,000 people died in Indonesia alone.

Even though 20 years have passed, survivors are still grieving the loved ones they lost to the giant wave that flattened buildings all the way to the provincial capital of Banda Aceh.

The infrastructure in Aceh has been rebuilt and is now more resilient than it was before the tsunami struck.

Early warning systems have been installed in coastal areas to alert residents of potential tsunamis, providing crucial time to seek safety.

The rebuilding efforts were made possible by the support of international donors and organisations, who contributed significant funds to help the region recover.

Schools, hospitals, and essential infrastructure that were destroyed by the disaster have been reconstructed with enhanced strength and durability, ensuring better preparedness for future challenges.

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 waves.

The tsunami also claimed the lives of over 8,000 people in Thailand, including many who remain missing, leaving a deep scar on the nation’s history. Nearly 400 bodies remain unclaimed.

Mourners shed tears and comforted each other as they laid flowers at the village’s tsunami memorial.

Around 300 people joined a modest ceremony with Muslim, Christian and Buddhist and prayers.

Urai Sirisuk said she avoids the seaside memorial park the rest of the year, because the loss of her 4-year-old daughter still cuts deep every time she’s reminded of it.

“I have this feeling that the sea has taken my child. I’m very angry with it. I can’t even put my foot in the water,” she said.

But, she said, “I still hear her voice in my ears, that she’s calling for me. I can’t abandon her. So I have to be here, for my child.”