Memorials were held for the victims of the tsunami that hit the Indian Ocean region, killing more than 200,000 people in one of modern history’s worst natural disasters.

On December 26, 2004, a magnitude-9.1 earthquake off Indonesia’s western tip generated a series of massive waves that pummelled the coastline of 14 countries from Indonesia to Somalia.

In Indonesia’s Aceh province, where more than 100,000 people were killed, a siren rang out at the Baiturrahman Grand Mosque to kick off a series of memorials around the region, including Sri Lanka, India and Thailand, which the tsunami hit hours later.

“I thought it was doomsday,” said Hasnawati, a 54-year-old teacher who goes by one name, at the Indonesian mosque which was damaged by the tsunami.

“On a Sunday morning, when our family were all laughing together, suddenly disaster struck and everything was gone. I can’t describe it with words.”

Some mourners sat and cried at Aceh’s Ulee Lheue mass grave, where about 14,000 are buried, while some villages held their own prayers around the province as they remembered the tragedy that devastated entire communities.

Indonesians will later visit a larger mass grave and hold a communal prayer in the provincial capital, Banda Aceh, while beachside memorials and religious ceremonies were starting in Sri Lanka, India and Thailand, some of the worst-hit countries.

A total of 226,408 people died as a result of the tsunami, according to EM-DAT, a recognised global disaster database.

There was no warning of the impending tsunami, giving little time for evacuation, despite the hours-long gaps between the waves striking different continents.

But today a sophisticated network of monitoring stations has cut down warning times.

Indonesia suffered the highest death toll, with more than 160,000 people killed along its western coast.

In Sri Lanka, where more than 35,000 people perished, survivors and relatives were to gather to remember about 1,000 victims who died when waves derailed a passenger train.

The mourners will board the restored Ocean Queen Express and head to Peraliya – the exact spot where it was ripped from the tracks, some 90km (56 miles) south of Colombo.

Nearly 300 people were killed as far away as Somalia, as well as more than 100 in the Maldives and dozens in Malaysia and Myanmar.