Moon
The Moon was, in a large number of worlds, the natural satellite of the Earth.
History
Lunar College Universe
A version of the Moon existed in at least one universe.
This version of the Moon was claimed by humanity at some point in its past, and the Lunar College of Selene was established upon it by NASA.
After Jenny Everywhere escaped from the Lunar College, she poured a mixture of extremely powerful fertilizer and her own saliva's bacteria onto the surface of the Moon in the hopes of establishing native life there. (COMIC: Bacterial Lunarversity)
Other references
One universe's Jenny, who often dreamed of adventures her other selves were having, once dreamt of a Jenny walking on the Moon. (PROSE: The Genesis of Jenny Everywhere)
Jenny Nowhere once wrote a piece of fiction where she and Jenny Everywhere ended up kissing on the Dark Side of the Moon, in a universe where it had a breathable atmosphere. (PROSE: Jenny Nowho?)