that described in the scriptures of that religion. There is also a generic Summerland for those who were atheists or agnostics in their previous lives. People who belong to religions that don't believe in reincarnation are surprised to find out when they get to heaven that they will have to reincarnate again within a few dozen to a few hundred years. Each heaven is believed to be an extensive structure composed of astral matter located on the astral plane about three or four miles (5–6 km) above the surface of Earth, above that part of the world where the particular religion that the heaven is meant for is most predominant. Theosophists also believe there is another higher level of heaven called Devachan, also called the Mental plane Heaven, which some but not all souls reach between incarnations—only those souls that are more highly developed spiritually reach this level, those souls that are at the first, second, and third levels of initiation. Devachan is several miles (around 10 km) higher above the surface of Earth than Summerland. The final permanent eternal afterlife heaven to which Theosophists believe most people will go millions or billions of years in the future, after our cycle of reincarnations in this Round is over. In order to go to Nirvana, it is necessary to have attained the fourth level of initiation or higher, meaning one is an arhat and thus no longer needs to reincarnate. Inhabitants of the various planes Occult writers such as Geoffrey Hodson, Mellie Uyldert, and Dora van Gelder had attempted to classify different spiritual beings into a hierarchy based on their assumed place and function on the planes of existence. Charles Webster Leadbeater fundamentally described and incorporated his comprehension of intangible beings for Theosophy. Along with him there are various planes intertwined with the quotidian human world and are all inhabited by multitudes of entities. Each plane is purported as composed of discrete density of astral or ethereal matter and frequently the denizens of a plane have no discernment of other ones. Other Theosophical writers such as Alice Bailey, a contemporary of Leadbeater, also gave continuousness to Theosophical concepts of ethereal beings and her works had a great impact over New Age movement. She puts the nature spirits and devas as ethereal beings immersed in macro divisions of an interwoven threefold universe, usually they belong to the etheric, astral, or mental planes.