Imagine you have a big toy train track. You can make it go around in circles, but sometimes you want to make it go faster or slower, so you change the train's speed. Scientists who study very small things, like atoms, do the same thing with machines called particle accelerators. They make tiny things go around and around in circles, but they can change how fast they go to study them better.
The Future Circular Collider (FCC) is like the big train track but much, much bigger. Instead of a train, it has tiny particles called protons that scientists send whizzing around so they can study them. The FCC will be one of the most powerful particle accelerators in the world when it's built, and it will help scientists answer important questions about how our world works.
Scientists have already built other big particle accelerators, but they keep making them bigger and more powerful because they want to study things they can't see yet. The FCC would be underground in Europe and would have a tunnel that is almost 100 kilometers long. That's like driving from your house to the beach and back twenty times!
Building the FCC will take a long time and a lot of money, but it's worth it because scientists think it will unlock secrets about the universe that we don't know yet. They want to learn more about dark matter, which is a mysterious thing that makes up most of the universe but we can't see it. They also want to study how the universe began and how the smallest particles work.
So, in short, the Future Circular Collider is like a really, really big toy train track that scientists use to study tiny things, and it will help us learn more about the universe around us.