Prime meridian

The prime meridian is like a big invisible line that goes all the way around the Earth from the North Pole to the South Pole. It is a very important line because it helps us figure out where things are on a map. It's like when you draw a picture and you put a line down the middle to help you know where everything goes.

The prime meridian is located at 0 degrees longitude, which means it divides the Earth into two halves, the Eastern Hemisphere and the Western Hemisphere. It helps us measure distances from one place to another and figure out what time it is in different parts of the world.

It's called the "prime" meridian because it is the starting point for measuring longitude. If you think of a piece of pie, the prime meridian is like the first slice that you cut. Without this line, it would be harder for people all over the world to communicate and work together.