From the years 108 BC to 450 AD the city of Jiaohe was the capital of the Anterior Jushi Kingdom in China
The city was built on a large islet (1650 m in length, 300 m wide at its widest point) in the middle of a river which formed natural defenses, which would explain why the city lacked any sort of walls. Instead, steep cliffs more than 30 metres high on all sides of the river acted as natural walls. The layout of the city had eastern and western residential districts, while the northern district was reserved for Buddhist sites of temples and stupas.
It was finally abandoned after its destruction during an invasion by the Mongols led by Genghis Khan in the 13th century