White Moon
The White Moon is the "egg" of Adam, a transport vessel created by the First Ancestral Race to send Adam to Earth. It landed on Earth well over 4 billion years ago, and came to rest deep beneath the region that would one day become Antarctica, under Mt. Markham (on Antarctica's Pacific coast, somewhat east of New Zealand). Buried under the surface, the White Moon formed a spherical underground cavity of gigantic size termed a "GeoFront", which was later codenamed "GF-01" (GeoFront-01).
In 2000, the secret Seele organization sent the Katsuragi Expedition to the White Moon in Antarctica, to conduct a "Contact Experiment" with Adam. This trigged the massive explosion of Second Impact, which destroyed the White Moon.
Sub-surface scans of the White Moon by the Katsuragi expedition note that it is physically identical to the Black Moon of Lilith under Tokyo-3, and that its surface structure is "clearly artificial".
The Black Moon which contains the GeoFront under Tokyo-3 is listed in production sketches as being 13.75 km in diameter, and as the White and Black Moons are physically identical, this would also be the size of the White Moon.