It tore through Aceh, Indonesia, with the force of an atomic bomb, obliterated hundreds of coastal villages in Sri Lanka and India, and smashed through luxury hotels in the beach resorts of Thailand.
The amount of death and destruction was almost unimaginable, and it spawned an unprecedented outpouring of humanitarian aid and record donations for relief and reconstruction.
But one year later, recovery in the Southeast Asia tsunami zone has fallen far short of expectations.
A frustrated Umi Kaosum -- who lost family, friends, her home, her entire village in Aceh -- knows about all the money that was donated. So why doesn't she have a home yet?
Government officials and aid agencies are dismayed that so many remain homeless, but the sheer scale of this disaster meant rebuilding more than just temporary housing. In Aceh, roughly $2 billion out of $7 billion has been spent on rebuilding roads, ports, water and sanitation facilities, and the first 13,000 houses. But 130,000 more homes are needed, and that could take three more years.
In Sri Lanka, the government declared many destroyed beach areas too dangerous and off-limits to construction. While bureaucrats have argued over where, when and how to relocate survivors, they've built only 6,000 new houses. More than 100,000 Sri Lankans still live in temporary shelters.
In Thailand there's been much greater recovery in the past year. From the beginning, the Thais were blessed with good infrastructure and much better government coordination.
Still, in badly hit Khao Lak, where more than 3,000 foreign tourists died, only one in 10 hotel rooms has been restored -- a major blow to the vital tourism industry.
More than 2,000 new homes have been built for Thai villagers caught in the tsunami, but hundreds have lost their tourism-related jobs and have little or nothing to live on.
There's no question -- recovery has gone slowly. But unlike many disasters, billions of donated dollars remain to be used.
The pace of recovery has started to pick up, and there are signs of optimism and hope returning -- hope that will still have to be tempered with a lot of patience.