Okay kiddo, when you go on a long journey, you need to know where to start from right? That's where the "zero mile" comes in. It's like a starting point for roads or railways that go on for really long distances.
Now, imagine a big city. In the center of that city, there might be a special spot where all the roads that go out to other places start. That spot is called the "zero mile" point.
So if you were going to go on a long road trip from that city, you might start from the zero mile and then keep going until you reach your destination. It's like the very beginning of your journey.
Just remember, the zero mile is just a starting point, it's not the end of the journey. You still have a long way to go!