Heading south from Anxi, the road winds through low hills and emerges in another plain extending toward the larger southern peaks. Stein traveled this route to the Ch'iao-tzu oasis, near which he explored a major Han-era fortress, some 500 yards square and noted many other old ruins. There was evidence that the fortified town had been occupied through the T'ang era and into the period of Tangut (Xi-Xia) rule prior to the Mongol invasion. The extent of these fortifications and the existence of additional watch towers further along the road at the Yulin "Thousand Buddha" Caves (Wang-fo-hsia) attests to the importance of this route. Here are two images of one of the Han fortifications near Ch'iao-tzu, although apparently not the one that Stein described.