Today in class the teacher wrote "Paris est la plus belle ville que j'aie jamais visitée". I was puzzled by why he added a "e" at the end of visité. From what I know, the sentence says Paris is the most beautiful city I have ever visited. He used belle instead of beau because ville is feminine, and he used the subjonctif passé after que because the sentence is subjective.
Please correct me if I'm wrong about anything. So my question is, why did he add an extra e at the end of the sentence? Is it because the subject (ville) is feminine or is it a direct object?