Souterrain

A souterrain is like a secret underground tunnel that people made a long time ago. It's usually made of stones and dirt, and it can be really small or really big. A long time ago, people used to hide in souterrains to avoid bad people or wild animals. They could also store their food and water there to keep it safe. People could get into a souterrain through a hidden trapdoor or a small hole in the ground. Nowadays, you can still visit souterrains in some places and learn about how people used to live a long time ago.