The Longmen Shiku (Longmen Caves)

From Lonely Planet, China.  Page 543:

In AD 494 the Northern Wei dynasty moved its capital from Datong to Luoyang.  at Datong the dynasty had built the impressive Yungang Shiku.  Now in Luoyang, the dynasty commenced work on the Longmen Shiku.  Over the next 200 years, more than 100,000 images and statues of Buddha and his disciples were carved into the cliff walls on the banks of Yi He, 16 km south of the city.  The caves of Louyang, Dunghuang, and Datong represent the peak of Buddhist cave art.  

Much damage was done to the sculptures at Luoyang during the 19th and 20th centuries by western souvenir hunters who beheaded just about every figure they could lay their saws on .  These heads now grace the museums and private paperweight collections of Europe and North America.  Among these were two murals that were entirely removed and can now be seen at the Museum of Art in New York and the Atkinson Museum in Kansas City.  The Cultural Revolution also took its toll when the Red Guards arrived with hammers - the ten thousand Buddha Cave was particularly damaged during this period.

The art of Buddhist cave sculpture largely came to an end around the middle of the 9th century as the Tang dynasty declined.  Persecution of foreign religions in China began, with Buddhism as the prime target.  Although Buddhist art and sculpture continued in China, it never reached the heights it enjoyed previously.