Shell keep

A shell keep is like a big castle that has a wall surrounding it. The castle has a tower where people can go up high and see everything around them. The wall also has towers where people can go up high and see if any bad guys are coming. Inside the castle there is a big yard where people can work and play, and there might be a well to get water from. The castle is strong and protects the people who live inside from any danger, like enemies or bad weather.