Hué used to be the capital of the Empire and thus the Imperial City was located there. Surrounded by the Citadel it still needs a lot of restoration work (due to US bombing) but is worth a visit.
There are also many shrines and emperor tombs in the region. I found the Tuduc Tomb to be quite impressive, especially because of the beautiful park which surrounds it.
Avoid the tour operators and rent a motorbike to explore the city and its surroundings. The Citadel is nice to drive around and gives you more time to explore the different area.
Hué was a quick stop on my way north and although a lot of people seem to avoid it, I would say it is worth a shot.Check out all the photos related to this post on Flickr »