There are 3 sites combined into this heritage. I visited 1 of them at Eastern Beijing called East Qing Imperial Tombs. A famous queen who was buried here. There had a myth about her tomb. She was buried with a large gem inside her mouth. Surprisingly, her corpse was mummified. However, a tomb thief stole the gem out and her corpse was turned into bone. The story seems not scientific but it would increase your interest to visit a site.