Listed by UNESCO in 1993 as a World Heritage Site, Hue's main attraction is the Citadel. The Citadel is at walking distance from the city downtown and you can walk across the Perfume River using the Trang Tien Bridge. You can also ride a bike or get by boat.
The Citadel dates from the times of Nguyen empire that ruled the region from 1802 to 1945 when the last king was forced to abdicate during the August Revolution. It was the capital of the empire. Walking along the streets and admiring the remaining buildings will certainly take you to old times that you probably watched in movies. Don't miss visiting the Flag Tower, the Royal Palace and the Royals Tombs. After the walk, relax where the Emperors did at Tinh Tam lake.
Unfortunately, many buildings inside the Citadel (specially Hue's Forbidden Purple City) were destroyed during 1968 Tet offensive. The following government did little to preserve the remaining or restore the damaged ones.
Other attractions are the toms and the pagodas that you can visit cruising the Perfume River, by car or by bike. They are about 1 mile south of Hue.
For more recent historical sites, visit the DMZ (Demilitarized Zone) north of Hue.
Hue Morning food market
For the early riser its worth walking through the main food market at dawn when it is busiest. It is across the bridge from the main tourist area, on the other side of the river, and turn right at the other side for about 400m. There is every kind of fruit and veg, live animals and hundreds of people carrying mountains of food through the crowds. Very photogenic in the early morning light.