Ash heap of history

So, kiddo, imagine you have a big pile of stuff that you don't need anymore. Maybe some old toys or clothes that don't fit you anymore. Now, that big pile is like the "ash heap of history". But, instead of toys and clothes, it's all the bad things that people did in the past.

For example, remember when people used to think it was okay to have slaves? That's something we put in the ash heap of history. It's something we learn about and remember so we don't make that mistake again.

So, the ash heap of history is like a big pile of all the mistakes and bad things that people did before. We don't forget about it, but we're always trying to learn from it so we can be better in the future.