A prominent location in many space and mecha anime, it is seen in one form or another in nearly every Gundam series.
As depicted in Gundam WIng
In Gundam Wing
In Gundam Wing, the Lunar Base was built by the Romefeller foundation as a manufacturing facility for mobile suits such as the Taurus, and later mobile dolls, specifically the Virgo. Although there are civilian recreational portions of the facility, it's primary function was as a military production facility. When the five scientists who designed the Gundams were captured by OZ, they were sent here to be detained while they designed the Mercurius and the Vayeate, and where secretly they developed the Gundam Deathscythe Hell and Gundam Altron. When Heero, Duo, and Wufei were captured, they too were detained at the Lunar Base. This was also the place where Lady Une was shot by Colonel Tsubarov in her effort to release the three Gundam pilots.