Contemporary knowledge about God, Evolution, and the meaning of human life.
Methodology of spiritual development.
The Egyptians received that knowledge directly from the Atlanteans. It included a description of the Supreme God (the Creator, the Primordial), Who manifested Himself both as Ra (an active state of the Creator that can be likened to the Divine Flame) and as Amun (another — the non-Fiery — Manifestation of the Creator). The Egyptians also knew how one can cognize God and develop oneself to Divinity.
Pharaohs were spiritual leaders of Egypt. The supreme priests of the Great Egyptian pyramid, which was constructed by the Atlanteans with the purpose of being an educational center (but not at all as a sepulcher), were their assistants.
From the population of the country the supreme priests selected those who were worthy of receiving the highest spiritual knowledge and then trained them. For the rest of the population, ritual religious ceremonies, intended for strengthening faith and raising morality were mostly conducted.
The list of principal steps of spiritual ascent, which worthy disciples studied in Egypt, consisted of initial purification of the consciousness abiding in the body, followed by stage-by-stage development of the soul, cognition and exploration of increasingly subtle layers of the multidimensional space, up to Mergence with the Creator.
The order of these stages and the interim results of their mastering turned out to be amazingly identical to that which God taught us here, in Russia, thousands years after those Egyptian mysteries took place! This clearly indicates that these stages are universal in nature.
The ancient Egyptian civilization also helped many souls attain complete Victory in their evolution. This was possible, among other reasons, because the Egyptian priests, always bearing in mind the tragedy of Atlantis, made efforts to prevent unworthy individuals from gaining access to the highest psycho-spiritual techniques.
“They kept their knowledge in the strictest secrecy, so that the very name Egypt itself became associated… with the greatest mystery.
“… The majority of those who had ever knocked on the doors of the temples of the mysteries, had never gotten admitted there; out of those who were admitted many overstrained their nerves or simply grew reluctant to undergo initiation because of the increasing level of difficulty of the tests which they had to pass before this. Thanks to this process of winnowing out,... the mysteries turned into one of the most closed institutes of antiquity, and the secrets that were hidden behind the tightly closed doors of the temples were confided only to those who had made a solemn vow never to bring them out of there. Everyone who had managed to get through those doors till the rest of their lives belonged to the secret society of people who continued living among the uninitiated masses but pursued higher goals”. 
… But the Egyptian civilization perished, nonetheless, — for the same reason as the Atlantic one.
In the beginning of the decline of the highest spiritual culture in Egypt the very fundamentals of religion were distorted. Most importantly, the primary purpose of spiritual efforts — Mergence with the Creator — was forgotten. And what was taught is merely a practice of “monadic” existence of the individual consciousness outside the body.
Later on, as in the case of Atlantis, black magic came to take the place of spirituality.
Paul Brunton writes the following about this :
“… The prophecy of Hermes — one of the most ancient prophets — came true. He said: ‘Oh, Egypt, Egypt, of thy religion nothing will remain… but graven words, and only the stones will tell of thy piety. Symbols… will be erroneously called gods, and Egypt will be found guilty of worshipping the monsters of hell’.
“With time the control of the mysteries transferred to unworthy egotistic individuals who sought to use the tremendous authority of the mysteries to their selfish ends. Even noble pharaohs sometimes bowed before their wicked will. Numerous priests started to engage in performing horrible rituals and using sinister incantations of black magic and turned into agents of dark forces of evil. Some of them transformed into… sheer devils in human form, who invoked the most disgusting hell personages for their no less disgusting purposes. In the most sacred places spirituality was driven out by witchcraft. In the conditions of spiritual darkness and chaos that set in Egypt, the mysteries soon lost their original character and lofty purpose. As time went by, finding worthy candidates for initiation was becoming an increasingly difficult task, thus their number was constantly decreasing.
“And the moment came when possessors of the highest knowledge… started to rapidly disappear, leaving for other worlds without coming back. The wicked people took their place.
“Those few who stayed longer than the others could not perform their spiritual mission, as before, all they could do is to mourn over their unfortunate lot. Always prepared to die, they were closing their sacred books, sorrowfully but quietly abandoning the temples and underground vaults, and, taking a last look at their ancient abodes, were silently leaving…”
God decided not to destroy the whole of Africa because of that. But Egypt got involved into warfare with its neighboring countries, lost its independence, and as the conquerors were replacing one another the ancient culture got completely destroyed.