I am not too fond of Hue’ city. It reminds me of Saigon: big city, lots of traffic, hordes of motorbikes, very noisy.
BUT.
Yes, there is a but. The Imperial City.
If there is one reason why Hue’ should make it on your travel itinerary, the Imperial City is that reason.

Hue’ was the capital of Vietnam from 1802 to 1945, during the Nguyen dynasty. Eleven of the Nguyen emperors are buried here.
A large Citadel, surrounded by a 10Km-long wall, was laid out at the beginning of the 19th century and contained the Imperial City. The latter is where offices, temples and royal palaces (in the Forbidden Purple City) were located. Definitely something not to be missed!

A visit to the Imperial City will take you 2-3 hours. Out of the original 148 buildings, only a few have survived fires and bombs but they are spectacular. Particular mention goes to the throne palace (Thai Hoa Palace), all gold and red – no photos are allowed inside, though.
A lot of restoration work has taken place in the Imperial City, and much is still ongoing – you will come across several examples during your visit.

The entrance ticket to the Imperial City will also give you access to the Royal Museum of Fine Arts, with its impressive collection of royal paraphernalia. The palace where the museum is located is a sight in itself.
Hue’ has been listed as UNESCO World Heritage site since 1993. And deservedly.