An estimated 230,000 people were killed or disappeared when huge waves slammed into 12 countries around the Indian Ocean on December 26th, 2004. The tsunami was caused by a magnitude nine-point-zero earthquake under the ocean floor off Indonesia's Sumatra island.
Residents of Aceh province, in northern Sumatra, gathered in mosques today to remember the 167-thousand Acehnese who died as the tsunami swept entire villages out to sea.
On Indonesia's Bali island, authorities held a tsunami drill to test a new alert system and raise public awareness.
Sri Lanka marked the anniversary with Buddhist prayers for its 35,000 dead, and by erecting the first of 100 coastal warning towers.
Multi-faith ceremonies were held in India, which lost 18 thousand people to the tsunami, and in Thailand, where 8,200 people died, about half of them foreign tourists.