The Masters teach that there are eight planes – the physical plane, the astral, the causal, the super-causal, Sach Khand, Alakh and Agam. And above all the cosmos, there is the eighth plane, Anami.
The physical, astral and causal planes are also called the three worlds. There mind, matter and maya (Illusion) entrap the soul. It is the home of gods, goddesses, angles and avataras, who are bound to these planes. Innumerable planes and sub-planes with various hells and heavens are located there.
But the eternal home of the soul is far beyond: Sach Khand, the region of truth, which is the first pure spiritual plane. All the planes below Sach Khand are liable to destruction at the time of Dissolution or Grand Dissolution, as the case may be. The idyllic home of the Saints and the Master-souls is located in Sach Khand and realization of this plane is their ideal.
Sant Kirpal Singh
"As above, so below. The Spirit and Power of God manifested in the vibrating holy Light, pervades all the four Grand Divisions of universe: Sach Khand, the abode of Truth or the Changeless Permanence in Its pristine purity, with the material cause (the mind) yet hidden and involved therein; the Brahmand or the egg of Brahman, the second Grand Division of the universe brought into being by the universal mind of elemental essence by the Will of the Supreme Being; and the next, Und, or the third Grand Division, called the astral world with mind-stuff in its subtle state; and lastly, Pind, or the physical world, the fourth Grand Division, the handiwork of the gross mind."
Excerpt from the book "Mystery of death", by Sant Kirpal Singh