On 26 December 2004, a 9.1-magnitude earthquake off the coast of Banda Aceh, Indonesia, triggered a deadly tsunami that killed more than 230,000 people and rendered millions homeless.
Many more found their lives were transformed forever by the natural disaster. Here, some share their stories.
Louis Cryer was 18 and in Sri Lanka with his mother Zoe and brother Felix
We were staying in an idyllic beach village called Unawatuna in Galle district. It took a matter of seconds for a wall of water of about 5ft (1.52m) in height to start coming in. It was a kind of surge which reached the first floor of our hotel.
It flattened walls, trees, and the buildings around us, before rising higher and higher. We tried to get people out. Miraculously, guests who had been in the room underneath us started popping up from the water.
One woman was trapped in her locked room because she couldn't find her key. She said the room filled up quickly with water and she took what she thought would be her last breath. Luckily she found the key and opened the door which then burst into pieces under the pressure.
Buildings were collapsing around us. We tried to pull out passing people trapped in the currents.
When the water finally subsided we made a run for higher ground and a temple that had become a make-shift safe refugee area. We set up camp in a hotel up on a hill and when it was safe to do so, we went back down to salvage anything we could. I remember seeing rooms full of mud and fish.
People came up to the temple with dead bodies. We carried one Italian woman with a suspected broken back through the debris to another hotel to get medical help. I met one guy who had been out surfing and was swept a few miles up the coast. He had to walk through all the death and destruction to find his family. Luckily he found them all.
One of the only positives to come out of it all was the humanity of it. It didn't matter about your nationality or religion. Everyone was checking on each other.
A few days later, once the road was clear, the High Commission sent coaches to take us back to a refugee centre in Colombo. We were fed, watered, offered clothes and flights home but we chose not go straight away. We wanted to stay to try and comprehend the reality of what had happened.
The main thing we felt was guilt. After seeing the devastation, we were lucky enough leave, but many were left with nothing.
Once in the UK, I put on an exhibition of photos I'd taken, spoke about it at our school and raised £3500 to send back to the village.
I gained a new-found respect for the sea. I never realised its power. It hasn't put me off going in the water, but I'm a lot more aware of what it can do.
Tom and Arlette Stuip were holidaying in Khao Lak,Thailand
We were having breakfast at the hotel on a terrace, overlooking the pool, the beach and the Andaman Sea. My husband Tom noticed the waiters were all pointing at the sea which was receding rapidly. It was a fascinating sight. People got their cameras out and walked towards the dry seabed. The beach was full of sunbathing tourists.
Tom had an uncomfortable feeling though. He lived for two years on the beach in California and had never seen a sea behave like this. Then it clicked: the trembling he heard earlier was an earthquake. The receding water was the prelude to a tidal wave.
Tom grabbed my hand and screamed, "Run!". At that same moment, he saw a high wall of water come crashing over the reef towards us at a speed of 40-50mph. We ran uphill fast. The water was right behind us. The noise was deafening.
Tom looked behind and saw the beach and pool area were a boiling mass of water. Palm trees, beach chairs and parts of bungalows were twirling around and people were frantically trying to hold on to something. We kept going for higher ground, up the steep hill into the jungle beyond it. We waited for two hours, knowing only few people would have survived the onslaught below.
When the sea looked calm again we descended to the hotel, and found many badly wounded people. We helped to get them onto the back of trucks taking people to hospital.
Then we were warned another tsunami was on its way so we climbed up into the jungle again, where we waited three more hours.
We then came down to the road there were cars and trucks loaded with the wounded. No one knew what to do or where to go. We did not want to go down to the lower level and see all the corpses that littered the beach.
There was no electricity, no cell-phone network nor radio, so we spent the night at a small restaurant stand.
The next day the road was clear, and we could start the long trip home. The floor of the bus station was covered with wounded people, all waiting for the bus to Bangkok. People nearly cried at the opportunity to use our cell phone and reach their families to tell them they were alive.
The guilt was hard to bear. I will never forgive myself for not going to the hospital with the wounded but mainly for coming back unscratched.
Ten years on and we are still looking at life with a lot of more appreciation. We feel connected with Thailand so that is why we continue with a Thai animal charity.
Kay Howells was snorkelling on Phi Phi Lei, Thailand
My partner and I had won a snorkling trip at a raffle on Christmas Eve at our hotel, Phi Phi Charlie on Koh Phi Phi. That raffle saved our lives.
We had been snorkelling in the water when the Thai guides started to call everyone back onto the boats. The water had receded rapidly from the shoreline and nobody knew what was happening. We were lucky that we managed to get back onto the boat as the waves came in, and the boat swiftly repositioned itself some few hundred metres away from the coast. However, as strange currents began to develop and the waves started to impact upon the bay, we saw people being swept away.
Longtail boats that had been closer to the shoreline snapped and sank like twigs. We can't believe how lucky we were to get back onto the boat as we don't know what happened to the people we had been snorkelling with and who had been swept away.
We just thought some localised freak incident had taken place but 30 minutes later the boat guides had a phone call from friends who told them Phuket and Phi Phi Don had been hit badly by a tsunami.
It became clear that Koh Phi Phi, where we had been staying, was devastated by the waves. Our hotel was destroyed, and it was only recently we found out that over half the people staying there were killed. We stayed in open water for the rest of the day waiting for more advice about what to do.
It wasn't until late afternoon that the boat took us back to Koh Phi Phi Don. It was then that the tragedy became apparent.
We were sailing in a soup of debris from the island which included TVs, fridges, holiday books and worse. It was just awful. We could see that the island was devastated and the infrastructure was shattered.
One man on board had a mobile phone. We all took it in turns to try to call home. Eventually I got through to my brother-in-law. I have never heard anyone speak with such worry and relief. He told me that everyone was so worried and had feared the worst.
We all decided to stay on the boat that night, moored out at sea. The boat was too small to have taken us all the way to Phuket. The only option we had was to wait for help to arrive in the morning. It was the longest night of my life and were it not for the camaraderie of those passengers on board and the wonderful generosity of the Thai people who owned and manned the boat, it would have been unbearable.
As the sun rose, we took the boat in to the harbour once again and waited for the larger boats to arrive. It was just awful. From our position on the water we saw hundreds of people all desperate to get off the island. They were huddled together on the pier in the harbour.
We eventually got the ferry boat to Phuket that morning and after a long wait we boarded an army plane back to Bangkok and a flight home.
We had lost all of our possessions but didn't care, we were so grateful to be alive. It was such an awful situation and such a random tragedy. Why did we take that boat trip that day? What if we had overslept? Why should we be the ones to survive and not so many others like us who didn't. It is senseless and random and just so utterly sad.
Every 26 December since the tsunami my partner and I take a walk on a beach and reflect on that devastating day. We will remember those who died again this year.
Produced by Sherie Ryder and Helen Dafedjaiye