Dating from the 1st century, Gaochang rose to power during the Tang dynasty in the 7th century and became the Uyghur capital in AD 850. It was a major staging post on the Silk Road until it burnt in the 14th century. Though the earthen city walls, once 12m thick, are clearly visible, not much else is left standing other than a large Buddhist monastery in the southwest. It's 30km from Turpan.
To the north, adjacent to an adobe pagoda, is a two-storey structure (half underground) that is purportedly the ancient palace. There is good signage in English in front of each structure, and the sheer scale of the place is incredible. Walking is possible but, due to its size, Gaochang is best covered by bike or electric buggy.