Okay kiddo, so imagine living in a big castle with all your family and friends. That's what a hakka walled village is like, but instead of a castle, it's a big community of houses with a wall all around it.
The hakka people are a group of Chinese people who used to live in different places, but because of wars and stuff, they had to move around a lot. They eventually decided to build these walled villages to keep themselves safe from bad guys and to have a big place to live together with all their different families.
These villages used to have really high walls with watchtowers and all kinds of cool defense things like gates and moats, just like in a castle. People would gather together in the village to farm, cook, and just hang out with each other. They'd build their houses close to each other inside the wall so they could all be safe and help each other out.
Nowadays, there aren't as many of these hakka walled villages left, but some still exist in China and are even visited by tourists who want to learn about their history and culture. So you see, it's like living in a big castle, but with your whole family and a whole community to protect and care for each other!