Hue's UNESCO-listed monuments are the main draw — the Citadel and Imperial Enclosure on the north bank, and the royal tombs scattered along the Perfume River to the south. A boat trip on the Perfume River is the classic way to see the tombs and the Thien Mu Pagoda, though renting a bicycle or motorbike gives you more freedom. Allow at least two full days for the major sights.