Located at 25 km (16 mi) southeast of the center of Dunhuang, the Mogao Caves, a system of nearly 500 temple grottoes, preserves an unparalleled treasure trove of Buddhist art, featuring exquisite murals and thousands of painted sculptures created over a span of a thousand years. The first caves were dug out in 366 CE and caves continued to be built at the site until the 14th century. The biggest buddha statue, at 35.5 m high, was constructed in 695 under the edicts from Empress Wu Zetian. It is housed in a prominent wooden 9-storey structure. Photography is forbidden inside the caves.