Luna

Luna is the only moon of the planet Earth. It is notable because it was the second world humanity colonised after Earth. From here, humanity spread out to cover their solar system and thennearly  the entire Galaxy. Luna is notable because it may have actually once supported some form of life for a short time. Now, however, Humans need bio-domes in order to live there, much like Mars and Venus.

Even up until as late as the 45th centuary Humans were still finding remnants of abandoned space probes and landing craft from the early Moon exploration missions. In the year 3535 PLF, the Lunar Rover was discovered in a small ditch, perfectly preserved due to the lack of atmosphere. A Museum called the Moon Museum was set up in Luna's capital city, Tranquility, to store and display all these forgotten relics. Also located on the Moon is the Luna Library, but thats a completely different story...

Not only that, but groovologists at the Lunacorona Musical Research Facility near the Moon's northen pole discovered the wreck of a starship, during one of their zero-gravity rehersals, that pre-dated Human existance. Interesting.

It should be noted that many Humans refer to Luna as simply 'The Moon', much like other species that life on planets with only one Moon.