So, a really, really long time ago, there were these people called Neanderthals. They were kind of like us humans, but they were different in some ways - they had a wider nose and a thicker skull, for example.
Now, Neanderthals lived in different parts of the world, like in Europe and Asia, and they lived there for thousands of years. Just like us, they hunted animals and gathered plants to eat, and they made tools and lived in groups.
But then, something happened. We're not exactly sure what, but some scientists think that it might have been the last Ice Age. See, the weather was really, really cold back then, and that made it harder for the Neanderthals to find enough food to survive. It was also harder for them to stay warm, because they didn't have things like warm clothes or houses like we do now.
So, as time went on, there were fewer and fewer Neanderthals. Eventually, they disappeared entirely, and we humans were the only ones left.
There are many theories about why the Neanderthals went extinct, but the most likely one is that they just couldn't adapt to the changing world around them. It's like, imagine you're playing a game and the rules suddenly change - it might take you a while to figure out how to keep playing. That's kind of what happened to the Neanderthals - the world changed, and they couldn't keep up.
But even though they're gone now, we can still learn a lot from the Neanderthals. They were really fascinating creatures, and studying them can help us understand where we came from and how we got to where we are today.