Okay kiddo, let me tell you about the Oppidum of Manching.
A long long time ago, even before your grandparents were born, there was a group of people called the Celts. They were a tribe of people who lived in Europe and had their own language and culture.
The Oppidum of Manching was a big city or town that the Celts built a very long time ago. It was located in what we now call Germany, and it was a very important place for the Celts.
The Oppidum of Manching was surrounded by big walls to protect the Celts from other tribes who might want to attack them. These walls were very tall and thick, and they had towers where people could watch for danger.
Inside the Oppidum of Manching, there were houses, markets, and all sorts of buildings where the Celts did their everyday activities. They even had their own special money called "galloping horses" that they used to buy and sell things.
The Celts who lived in the Oppidum of Manching were very skilled at making things like jewelry, weapons, and pottery. They even made their own beer!
The Oppidum of Manching was a very special place, and it helped the Celts to live together and be safe. Even though it doesn't exist anymore, we can still learn a lot about the Celts and their way of life by studying the Oppidum of Manching.