As the world remembers the tsunami that hit south-east Asia a year ago, BBC Wales reporter Iolo ap Dafydd travelled to Indonesia to see how the people of Sumatra have coped as they try to rebuild their lives.
Much of Aceh was completely flattened
If you can imagine a 90ft wave with the destructive power equivalent to 100bn tonnes crashing onto Prestatyn or Rhyl along the north Wales coast, you might have some idea of what Sumatra in Indonesia endured a year ago.
When the Boxing Day earthquake erupted, lifting the sea floor, it created a wall of water.
The nearest land was Sumatra's west coast and Aceh province in the northern tip.
Up to 250,000 people died as a result of the tsunami, in a dozen different countries, but none suffered as great a loss as Indonesia.
Mile after mile of the coastline is desolate, and barren wasteland. In parts it resembles a huge bomb site - like Hiroshima or Nagasaki.
More than 100,000 are still living in tents
And yet many locals told me: "You should have seen it a year ago."
In some coastal villages, new wooden houses are being built. Nowhere near enough, as Naveed Chaudhri from Oxfam told me.
"It's a complicated business," he said. "We've been able to build since last May. We've completed some 200 houses, and we're working in these three villages near Banda Aceh.
"In this particular village Aloe Deah Teungoh we've got about 54 houses built another 27 under construction. We hope to have - across all our work in Aceh - over 700 houses built by the end of this month."
Mr Chaudhri has family in mid and west Wales, but he is normally based at Oxfam's headquarters in Oxford.
He agrees more houses should be built, and quicker, but points out that, in a district called Meuraxa, more than 31,000 people lived in 17 villages before the tsunami. Now that number is less than 6,500. The conclusion is obvious: fewer houses are needed now.
Many locals might disagree with that argument. With half a million displaced people still in the Indonesian province, 100,000 have braved a whole year living in tents.
Arjiani is a 30-year-old widow caring for two sons, aged five and two. Her husband was a fisherman in Calang. He died last December and she walked for seven days to reach the safety of the camp on the outskirts of Banda Aceh.
"What can I do? " she asked. "If I go, there's no house at home anymore. If I could go back I would. But I can't, so I have to stay here."
At the camp in Lamreung there is clean water and supplies of food which are delivered by charities like Care and Oxfam to the 1,100 people who live there.
Arjian is certainly not alone - there are 50 other "female-headed families". That is the phrase used by international non-governmental organisations (NGOs) to classify the families where the men have died.
Eric Morris, who is co-ordinating the United Nations' response to Aceh, said the the plight of the 100,000 people who have lived for 12 months under canvas is "unacceptable".
Over the next few months, the International Federation of the Red Cross aims to deliver 20,000 steel structures as temporary homes, to try to improve the situation.
Log on to the BBC Wales news website on Tuesday to read Iolo's report on the progress being made in Sri Lanka after the tsunami.