I spent today at Hue, the capital during Vietnam's latest dynasty, early 19th century to 1945. The most impressive thing about it was the scale. The buildings went on for miles, it seemed. In reality, the main compound is about one square kilometer.
Some of the buildings were well-maintained, others were in disrepair, and interspersed were ramshackle worker or tool huts, broken rock and even garbage. This picture from the moat demonstrates the contrast a bit.
The temple at Tien Mue was almost more impressive. It was in a scenic location, with views over the river and to the mountains. It had some impressive Buddha statues, and the gardens were, well, zen-like.