Grotto-heavens are a type of sacred Taoist site. Grotto-heavens are usually caves, grottoes, mountain hollows, or other underground spaces.
In the Tang dynasty, immortals were thought to have lived in certain immortal cave-heaven lands that existed between heaven and earth, shrouded by colorful clouds; wonderful flowers, peach trees and fragrant grass were often said to have grown there.[1]
Because every community was supposed to have access to at least one grotto, there were many of them all over China. They were first organized systematically in Tang times by Sima Chengzhen (Chinese: 司馬承禎) (647–735, see Zuowanglun) and Du Guangting (Chinese: 杜光庭) (850-933).[2] The most sacred of these sites were divided into two types: The ten greater grotto-heavens and the thirty-six lesser grotto-heavens.[3]
Locations of the ten greater grotto-heavens are as follows: