1. A lesson two weeks before
Two weeks before Christmas 2004, in a school in England, a room of ten-year-old children sat through a lesson about the sea.
Their teacher, Mr Kearney, told them what happens when the floor of the sea moves. He told them that the water does strange things first — that it can bubble, that it can come in when it should go out — and that the thing itself is not the high blue wall you see in films. It is more like the sea getting up and walking into the land and not stopping.
Then he showed them a film of a wave in Hawaii, and the lesson ended, and they all went home for the holiday.
One of the children in that room was Tilly Smith. She was ten years old. Nine days later she was on the other side of the world.
2. Ten in the morning
On the morning of 26 December 2004 Tilly was on the sand at Mai Khao, on the island of Phuket, in Thailand, with her mother and her father and her little sister. It was a hotel beach and it was full. There were about a hundred people on it.
No one there knew that the floor of the sea moved that morning, eight hundred kilometers away.
Tilly was walking near the water with her mother when she saw that the sea was wrong.
It was not going back. It came up the sand and it stayed, and the next water came up on top of it, and the whole front of it was white and full of bubbles, and it was making a sound she did not know.
She has explained it many times since. She was not afraid at first. She was only certain — because she knew the word for it, and because she saw the same thing two weeks before on a film in England.
"There is going to be a tsunami," she said.
3. A hundred people
Her mother did not understand the word. Tilly said it again. She said it to her father. She would not stop saying it, and she started to cry, and in the end her family believed her — not because they knew anything about the sea, but because a ten-year-old does not usually do that.
Her father went to the hotel people. They walked along the sand. Some of them were already worried; a call came in from another beach further along the island. The message went out in two languages, and people picked up their things and walked off the beach and up toward the hotel.
It took a few minutes. The beach was empty when the water arrived.
At Mai Khao that day the sea came over the sand and into the ground floor of the hotel, and no one there died. Along the rest of that land, and around that whole sea, about two hundred and thirty thousand people died before the day was over.
Tilly Smith was ten years old, and a hundred people walked off a beach because she told them to.
She has never liked the way people tell it. She says the hotel men were already moving. She says her father is the one they listened to. She says she only knew what she knew because a teacher stood in front of a room of children in December and explained it well.
That is more or less the point. No one stopped the wave. It was simply that one child on that beach got the information two weeks earlier — and when she saw the thing itself, she knew it.