Gaia ("land" or "earth", also spelled Ge or Gaea) is the Earth in Greek mythology. She was the daughter of Chaos, or according to another version Aether and Hemera, and the mother of Uranus (also her husband), Ourea and Pontus. Uranus and Pontus were of Gaia alone and born without a father. Her Roman equivalent was Terra.
The mythological name was used in 1969 by James Lovelock for his Gaia hypothesis, which was later developed by Lynn Margulis into a Gaia theory. The hypothesis proposes that living organisms and inorganic material are part of a dynamic system that shapes the Earth's biosphere. Earth itself is viewed as an organism with self-regulatory functions. The theme behind the movie Final Fantasy: The Spirits Within is about this philosophy of Gaia, which is also embraced within parts of the New Age and movement, and by some environmentalists.
With Uranus, Gaia had three sets of children: one-hundred armed giants called Hecatonchires and one-eyed giants called Cyclopes were the youngest, and significantly later, the Titans. Occasionally, the Erinyes were considered a fourth set of children by Gaia and Uranus.
Uranus hid the (Hecatonchires) and the Cyclopes in Tartarus so that they would not see the light, rejoicing in this evil doing. This caused pain to Gaia (Tartarus was her bowels) so she created grey flint (or adamantine[?]) and shaped a great sickle and gathered together Cronus and his brothers to ask them to obey her. Only Cronus was willing to do the deed, so Gaia gave him the sickle and set him in ambush. Cronus jumped out and lopped off his father's testicles, casting them behind him. From his blood on the Earth came forth the Gigantes, Erinyes and Meliae. From the testicles of Uranus in the sea came forth Aphrodite. For this, Uranus called his sons Titans, meaning "strainers" for they strained and did presumptuously a fearful deed, for which vengeance would come afterwards.
As Uranus had been deposed by his son, Cronus, so was Cronus destined to be overthrown by his son. To prevent this, he swallowed his children as soon as they were born. Gaia gave Cronus' wife, Rhea the idea to save the last child, Zeus, by giving Cronus a stone wrapped up like a baby. Gaia then raised Zeus (according to some versions of the story), who eventually rescued his brothers and sisters, eaten by Cronus, as well as releasing the Cyclopes, Hecatonchires and Gigantes from Tartarus. Together, Zeus and his allies overthrew Cronus.
Gaia made Aristaeus immortal.