Celea is one of the Apunian (ETs from Apu) Extraterrestrial bases on the dark side of the moon, it has been operating for more than 10,000 years.
It was built to fulfill two functions: balance the lunar orbit, and observe what was happening on Earth.
Celea was conceived to be a strategic observation point, and protect the planet against possible interventions by negative extraterrestrial civilizations.
The Moon was found by the beings of Apu as a completely dead and uninhabitable satellite, a product of the Orion Wars.
They adapted to the Moon and have underground galleries there.