According to ancient Sumerian texts, the Anunnaki are described as "those who descended from heaven", they were considered a powerful race of extraterrestrial beings who were believed to have played a role in the creation of humanity hundreds of thousands of years ago.
The Anunnaki, referred to as "those who descended from heaven," were considered the main deities by the ancient Sumerians, Akkadians, Assyrians, and Babylonians, who inhabited Mesopotamia, the region now known as Iran and Iraq.
Enki was a prominent god in Sumerian mythology and the patron of the city of Eridu. According to ancient Mesopotamians, Eridu was the first city to be established worldwide. Enki is credited with the creation of humanity in the Epic of Atrahasis, a Sumerian epic poem that tells the story of creation and the Great Flood. The poem depicts that mankind was created to serve the gods.
As the human population rapidly multiplied and their lifespans were long, the chief god Enlil grew increasingly troubled by the noise and commotion caused by humans. He decided to send various catastrophes to Earth in order to reduce the population. In each instance, the humans turned to Enki for guidance on how to survive these disasters.
Enlil ultimately decided to eradicate all of humanity through a great flood. Enki, unable to prevent Enlil's plan, came down to Earth to save Atrahasis, whom he deemed a righteous person. Enki instructed Atrahasis to construct an ark to save himself from Enlil's wrath. All other humans perished in the flood.
After the flood, Enlil proposed the creation of a new human race, but this time with certain limitations. These limitations include being less fertile, having shorter lifespans, and being more vulnerable than the previous generation of humans.
The Planet Nibiru

Zecharia Sitchin, an Azerbaijani author, presents an alternative viewpoint on the origins of humanity in his book series, "The Chronicles of the Earth."
Zecharia Sitchin interprets the Anunnaki as Ancient Astronauts, positing that "those who came from heaven" were an extraterrestrial race of intellectually superior beings who imparted knowledge of astronomy, architecture, mathematics, medicine, metallurgy and writing to the Sumerians.
According to Sitchin, modern Homo Sapiens were the outcome of genetic manipulation and the Anunnaki created the Sumerians by merging a hominid's DNA with their own.
Zecharia Sitchin, an expert in ancient languages, reinterprets the creation myth of the Earth, basing his interpretation on the Babylonian poem Enuma Elish, which was found on cuneiform clay tablets from the library of the Assyrian king Ashurbanipal in Nineveh. He notes similarities between this poem and the biblical story of Genesis.

According to Sitchin's interpretation, Nibiru, referred to as the "Twelfth Planet," has an elongated elliptical orbit with a period of 3,600 years around the Sun and is inhabited by beings similar to humans.
Sitchin suggests that one of Nibiru's two moons may have collided with Tiamat, an ancient planet between Mars and Jupiter, leading to its fragmentation, with one part becoming the Earth and its moon, and the other being sent into a new orbit millions of years ago.
Sitchin further suggests that the planet Nibiru itself later collided with the remaining fragment of Tiamat, causing it to shatter and form the Asteroid Belt.
In an effort to address the issues plaguing their planet, the Nibiruans began to explore the Solar System in search of gold. About 450,000 years ago, Nibiru's orbit brought it close to Earth, and some individuals were sent to our planet via spacecraft.
They set up their bases in ancient Mesopotamia and southern Africa where they discovered significant gold deposits and established mines to extract valuable minerals. However, the Nibiruan leaders did not perform the mining themselves, instead, they sent the Anunnaki to carry out this task.
The Anunnaki were tall beings, over 10 feet, with white skin, long hair, and beard. Despite their physical and intellectual abilities, they were treated as a form of slave labor. As a result, the Anunnaki eventually rebelled against their supervisors, demanding the creation of a lesser being to take their place.
The Nibiruans accepted the Anunnaki's request and decided to create a new species by combining their own genetic material with that of the most advanced primates on Earth.
The Creation Of Humanity
Initially, Enki and Ninmah, the primary scientists, created strong and large beings to work in the Anunnakis' mines. However, these beings could not reproduce, so they had to be continually created for optimal mineral production.
Enki and Ninmah created several versions of beings until they found one that could reproduce. This led to the creation of the first human species, Homo erectus.
As Nibiru moved away from Earth, some of the "gods" returned to their home planet until the end of the 3,600-year cycle (a period known as Sar to the Sumerians). Meanwhile, a group of the Anunnakis stayed on Earth to oversee the gold mines and their new worker beings.
However, the new humans, created in the image of their creators, began to have conflicts over earthly matters, forming alliances and rebelling against their masters, similar to the conflicts that had occurred among the Anunnakis.
Many of them managed to escape the mines and establish themselves as independent beings elsewhere on Earth, starting a new, but primitive, way of life. After 3,600 years, the orbital cycle was completed again, Nibiru approached Earth once more, and the Anunnaki leaders returned, but found that the situation had once again spiraled out of control.
They punished the Anunnaki by making them work in the mines once again. During their brief visit, they started new experiments to create a more superior race of workers. Thus, chief scientist Enki and physician Ninti used genetic manipulation and in-vitro fertilization to design a new species with greater cognitive ability, capable of thinking, speaking and reproducing, creating Homo Sapiens.
"Man and woman he created them; and he blessed them, and called them by the name of Adam, in the day they were created." Genesis 5:2.

The Hebrew term Adam, therefore, does not refer to an individual person, but instead refers to the initial group of human beings called Adamites or "those who are of the earth".
According to Sitchin, ancient texts suggest that these "gods" guided the development of the Sumerian civilization and that the human monarchy was established to serve as a link between humanity and the Anunnakis.
After the creation of humans, one major problem remained: the other humanoid beings that had escaped and spread throughout much of the world. The solution was a massive flood caused by disturbances in the Solar System that lasted for about 12,000 years.
The Anunnaki then decided to leave the planet and let all of its inhabitants be destroyed by the flood, but Enki, believing that his recent creation was too unique and perfect, chose to help and save humans by instructing Atrahasis to build a large ark, in a story that mirrors the biblical tale of Noah.

According to Zecharia Sitchin, Nibiru's last visit occurred in 556 BC, and given its 3,600-year orbit, it is expected to return in the Third Millennium. However, he believes that the Anunnakis may arrive sooner, between 2090 and 2370, and that their arrival will coincide with the astrological transition from the Age of Pisces to the Age of Aquarius.