The Divine All-Mother, believed by many to be the source of all life. According to many creation myths, Gaia predates the eternals and even the titans. There are some who claim that Aecus itself is Gaia, with all elemental forces merely her aspects.
Gaia has many symbols. Here is one that agents of the SPI encountered at Evershroud Manor during case 14:
Chronicle
Case 14e03
Depicted on the portal as the Divine Mother, predating the eternals and representing the source of all life.