Eight hundred feet above the entrance to the Bamiyan Valley are the ruins of the Red City. This fortress of sun-dried red clay was once home to 3,000 people and was the primary defense for the valley during 12th and 13th centuries. In 1221 it was attack by the grandson of Genghis Kahn. The fort held and the grandson was killed.
In revenge Genghis Khan himself attacked the valley and destroyed everything including the irrigation systems. The Red City was never rebuild after this attack. The ancient mud walls only still stand because there is little rainfall in this desert country to destroy them.