In Greek mythology, Gaia personifies the earth. She was born of Chaos, and brought forth the sky, the mountains, the sea, and the god Uranus. After hooking up with Uranus, Gaia gave birth to the first races of Divine beings. The three Cyclopes were one-eyed giants named Bronte, Arges and Steropes. The three Hekatoncheires each had a hundred hands. Finally, the twelve Titans, led by Cronos, became the elder gods of Greek mythology.
Uranus wasn't thrilled about the offspring that he and Gaia had produced, so he forced them back inside her. As one might expect, she was less than pleased about this, so she persuaded Cronos to castrate his father. Later, she predicted that Cronos would be overthrown by one of his own children. As a precaution, Cronos devoured all of his own offspring, but his wife Rhea hid the infant Zeus from him. Later, Zeus dethroned his father and became the leader of the gods of Olympus.
Gaia herself caused life to spring forth from the earth, and is also the name given to the magical energy that makes certain locations sacred. The Oracle at Delphi was believed to be the most powerful prophetic site on earth, and was considered the center of the world, due to Gaia's energy.
The concept of an earth mother is not exclusive to Greek myth. In Roman legend, she is personified as Terra. The Sumerians honored Tiamet, and the Maori people honored Papatuanuku, the Sky Mother. Today, many Wiccans and NeoPagans honor Gaia as the earth, or as the archetypical embodiment of the Earth's power and energy.