Looking into what happened to Atlantis and Lemuria, I came across a passage from Sheldan Nidle giving a capsule history of Earth, which I’d like to post here.
Spiritual Hierarchy and the Galactic Federation Update, as received by Sheldan Nidle, July 1, 2014 at https://www.paoweb.com/sn070114.htm.
This planet [Earth] was a water world, filled with what you might think are very unusual creatures. The worst of these was a large predator and our ancestors had climbed over a series of craggy mountains to escape it. There, they developed into great fishermen and began to spend a vast amount of time at sea. Eventually, they lost their dense body fur and took on some of the characteristics of a marine mammal.
Around six million years ago, land cetaceans visited them from the Solis system. These gentle Beings asked them if they wanted to become fully-conscious Beings and eventually migrate to their former homelands. They were reluctant at first. However, the intervention of the Spiritual Hierarchy convinced them to do so. They were then granted full consciousness and met with other such souls from the stars, which surrounded Vega.
These meetings led to the formation of a Light confederation, which began to slowly expand its influence across the Lyra constellation. Four million years ago, they had reached the star Sirius and had morphed into a new organization, the Galactic Federation of Light. It was this sacred union which eventually colonized the Solis system. These colonies were ravaged by the Ancharan Alliance and forced to flee.
The colonists returned around 900,000 years ago and decided to only settle on Gaia. This group set up its headquarters in Inner Earth and also settled on a large island continent known to you today as Lemuria. This surface colony began to slowly expand. Its task was to support and maintain the various ecosystems.
Around 300,000 years ago, Earth was colonized by Beings from Centaurus and the Pleiades. Most of them went to a large island continent in the present-day Atlantic Ocean. Its inhabitants called this new colony “Atlantis.” It soon became a silent rival of the Lemurians. Around 50,000 years ago, the Lemurians gave each of its colonies equal status. The Atlanteans saw this as a possible opportunity to exert their dominance over the surface lands of Earth.
Approximately 25,000 years ago, the Atlanteans and their dark allies struck and destroyed the surface lands of Lemuria. The Lemurians retreated to their Inner Earth realm. This left the Atlanteans in charge of the surface lands. Over the millennia, the Atlanteans began a policy of banishing the many children of the ruling elites who strongly opposed them to a peninsula in the Mediterranean Sea called “Ionia.” The Atlanteans eventually attacked this colony.
The Ionian scientists had prepared for this eventuality with a series of special devices. With these they were able to counter this threat. Atlantis was consumed by its own weapon and soon sank beneath the waters. The residents of Atlantis and their global allies fled to another world, which orbited a star in the Centaurian constellation, known to you as Beta Centauri.
This disaster left behind two groups of Beings. The first were a group of special human hybrids called, in your legends, the Anunnaki. The second was your limited-consciousness ancestors. These groups, with the help of Heaven, soon formed a symbiotic relationship.
Heaven desired that your ancestors survive and learn a number of vital lessons, which were to become useful once the Light returned in full force to your world. This strange relationship, which consisted of the Anunnaki as “gods” and your ancestors as their devoted followers, continued for some 13,000 years. The time arrives for this to end and for you to resume your former state.
This stage of your long journey is merely the beginning of how you are to be made fully conscious once again. We are here to be your mentors and to permit your return. The Anunnaki left behind a ruling group that morphed over the millennia into what you know as the dark cabal. This group is being ousted from power. It is aware that its time has come.