Why did the Roman Empire collapse, and what were its main causes?

The Roman Empire fell because it had too many problems all at once, like a big, tired kid who can't keep up with everything.

Imagine Rome as a giant toy castle, built by lots of kids working together over many years. It was strong and beautiful, but as more kids came to play, the castle got bigger and harder to manage.

At first, having more kids was fun. But soon, there were too many people to feed, too many jobs to do, and not enough coins (like gold stickers) to go around. Some kids started fighting over the best toys, this is like how different parts of Rome started to argue with each other.

Also, the guards who protected the castle got tired. They used to be strong and brave, but now they were weak and lazy, just like the Roman army at times. When bad guys came (like pirates or enemies from far away), the guards couldn't stop them easily.

These problems all added up until the big toy castle finally fell down, that's how Rome collapsed!