Ancient capital, Mongol empire. Its ruins lie on the upper Orhon River in north-central Mongolia. It was settled c. 750. Genghis Khan established his headquarters there in 1220. In 1235 his son and successor, Ögödei, enclosed the city with walls and built a palace. Chinese forces invaded Mongolia and destroyed Karakorum in 1388. It was later partially rebuilt but was abandoned by the 16th century. The ruins are included in a regional UNESCO World Heritage site designated in 2004.