More than 230,000 people died across south-east Asia when a tsunami unleashed devastation on December 26, 2004.
Thousands converged in cemeteries in the Indonesian province of Aceh on Thursday to commemorate 15 years since a devastating tsunami.
About 230,000 people lost their lives when a 9.1-magnitude undersea earthquake struck on the morning of December 26, 2004.
It happened near the Indonesian island of Sumatra and triggered a massive tsunami.
The immense waves claimed lives in Thailand, India, Sri Lanka and the Philippines but it was in Indonesia that their impact was the most devastating with more than 160,000 deaths recorded, most of them in Aceh province, the northwestern tip of Sumatra.
Hundreds of thousands were also left homeless while crucial infrastructure — including roads, electricity and water networks as well as schools and hospitals — was flattened.
Nurhayati, who lost her youngest daughter in the natural disaster, was among those who attended the commemoration in Aceh Besar.
"I come here every year because I just miss her so much. She was only 17 and had just started university," she tearfully said.
"It's been 15 years but even today, every time I see the ocean, even on television, I tremble and I have the impression a wave is coming," the 65-year-old added.
Deny Eriyanto, who also lost relatives to the waves, commemorated the tragedy in a ceremony held in a convention centre in the city of Sigli.
"We always come to the mass graves of tsunami victims because we don't know where our family is buried," he said.
Aceh's acting governor Nova Iriansyah praised the province's people who were "able to overcome suffering and rise again" and thanked his fellow countrymen as well as all those who assisted the region after the disaster.
"On behalf of the government and people of Aceh today, we formally want to thank more than 150 countries that have been involved in helping rehabilitation and reconstruction," he said.
Located on the Pacific Ring of Fire, Indonesia is particularly vulnerable to seismic and volcanic activity.
Last December, over 400 people died in the country in a tsunami triggered by undersea landslides in the Sunda Strait.