This is a description of the World-Heritage-registered ancient city of Hue by UNESCO.
This video should give you an idea of what the Citadel looks like.
Here is my encounter with the walled city over a two-day period. I just walked around the wall on the first day when it was cloudy but not raining. On the third day I went back to go inside the wall and explore the Forbidden City which I did but it was raining and rather wet. 😦