Shangri-La is a place that is reported to exist in Tibet in the Himalayan Mountains. It is said to be a mystical valley, isolated from the rest of the world, and led by a monastery of Tibetan lamas. The inhabitants of Shangri-La are supposed to be almost immortal, living for multiple lifetimes and showing signs of aging extremely slowly. All the cultural treasures of the world are said to be stored there as well as all the wisdom of the human race which is stored in the minds of the people who live in the valley.
The idea of a lost kingdom in the Himalayas has been part of the Buddhist teaching for hundreds of years. There have been numerous attempts to find Shangri-La over the years going back to the time of the 16th century Mogul emperor Akbar. There is the tale of a Jesuit missionary named Antonio Andrade in the court of Akbar who set out in search of the Shangri-La. After following yogis and wandering pilgrims, he eventually did find an impressive and wealthy kingdom, and his account of his adventurous journey having been lost for over 2 centuries, was rediscovered in Calcutta in the 19th century. Given how large and inhospitable the Himalayan area, it is still possible that what is said to have once been Shangri-La still exists, even if it is in an unrecognizable state.