Maijishan Grottoes

Maijishan Grottoes are a series of nearly 200 man-made caves cut in the side of the hill of Majishan in northwest China during the 4th century and featuring thousands of sculpted statues and murals carved into sandstone cliffs. They were also, the ancestral home of the Chinese Assassins until 1524, when the Templars begin a purge of their ennemies. The grottoes were then converted into a secret Templar prison.

Reference

 * Blog.ubi.com