Those without a special passion for cave temples should save themselves for Dunhuang, but for those seeking a complete picture of the transmission of Buddhist art and ideas, this site might offer some more insights. Seventy-eight kilometers (48 miles) from Kuqa, the site can be reached by arranging a tour or hiring a taxi (¥200-¥250 round-trip).
Currently, only the Western Section (Xi Qu) is open to the public, and none of the caves actually have much in them except for Cave 17, which has several walls worth of Buddhist cave drawings intact. Even so, the blue tones in some of the caves, produced by lapis lazuli from Afghanistan (which was worth twice its weight in gold during the Middle Ages), are stunning. To visit other caves, you'll have to fax a letter in advance to ask for permission.
The site predates Dunhuang, and painting continued until the Ming dynasty, when Islam fully displaced Buddhism. The site lies in a spectacular and remote valley beside the Muzart River, where the lack of Han influence is striking. Persian, Gandharan, Indian, and Grecian motifs dominate. Black suns, Garuda (a bird god borrowed from Indian mythology), and Apollo riding in a chariot are common decorations on the axis of the roofs. Most caves have a central pillar for perambulation, with a sleeping Buddha at the rear, presided over by mourning disciples. Buddhas and bodhisattvas are lean and muscular, with Indian features.
Unfortunately, little statuary remains, and many of the wall paintings have been removed to Europe and Japan. The eyes and mouths of most remaining images have been defaced by Muslim iconoclasts. There are also some inappropriate recent additions, particularly a ridiculous man-made lake less than 180m (600 ft.) from the caves, which depend on aridity for their preservation. The Exhibit of Kizil Artifacts, just inside the entrance, is worthwhile, especially if you've already made the trip out here. It features reproduction drawings from many caves that you won't be allowed to enter, and other artifacts.