The Liao fell to the Jurchen Jin dynasty in 1122, which gave the city to the Song dynasty and then retook it in 1125 during its conquest of northern China.  In 1153, the Jurchen Jin made Beijing their "Central Capital", or Zhongdu. The city was besieged by Genghis Khan's invading Mongolian army in 1213 and razed to the ground two years later. Two generations later, Kublai Khan ordered the construction of Dadu (or Daidu to the Mongols, commonly known as Khanbaliq), a new capital for his Yuan dynasty to the northeast of the Zhongdu ruins. The construction took from 1264 to 1293, but greatly enhanced the status of a city on the northern fringe of China proper. The city was centered on the Drum Tower slightly to the north of modern Beijing and stretched from the present-day Chang'an Avenue to the northern part of Line 10 subway. Remnants of the Yuan rammed earth wall still stand and are known as the Tucheng.