More than 25 years ago, Saroo Brierley lived in rural（农村）India. One day, he played with his brother along the rail line and fell asleep. When he woke up and found himself alone, the 4-year-old decided his brother might be on the train he saw in front of him-so he got on.

That train took him a thousand miles across the country to a totally strange city. He lived on the streets, and then in an orphanage（孤儿院）. There, he was adopted by an Australian family and flown to Tasmania.

As he writes in his new book, A Long Way Home, Brierley couldn't help but wonder about his hometown back in India. He remembered landmarks, but since he didn't know his town's name, finding a small neighborhood in a vast country proved to be impossible.

Then he found a digital mapping program. He spent years searching for his hometown in the program's satellite pictures. In 2011, he came across something familiar. He studied it and realized he was looking at a town's central business district from a bird's-eye view. He thought,  “On the right-hand side you should see the three-platform train station”—and there it was. "And on the left-hand side you should see a big fountain"-and there it was. Everything just started to match.

When he stood in front of the house where he grew up as a child, he saw a lady standing in the entrance. "There's something about me, " he thought—and it took him a few seconds but he finally remembered what she used to look like.

In an interview Brierley says, "My mother looked so much shorter than I remembered. But she came forth and walked forward, and I walked forward, and my feelings and tears and the chemical in my brain, you know, it was like a nuclear fusion（核聚变）. I just didn't know what to say, because I never thought seeing my mother would ever come true. And here I am, standing in front of her. ”