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. 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.