The lunar landing sites are historical monuments and of course protected. But that doesn't mean they have not been affected by time. The Apollo 14 landing site got hit by a crashlanding cargo transport a decade before the Fall, and the Apollo 17 site was recently vandalized by unknown perpetrators (the Ring of Steel, a radical breakaway faction of the Steel Liberators, have claimed responsibility).
However, Apollo 11 near Nectar has so far remained untouched. Helium mining has been banned from the vicinity, and a protective diamond dome erected around the site with the lander, equipment and the famous footprints. Pilgrims (there are a few each year, despite the easier access through XP and VR) get to watch the site from a ramp around the dome.
Unfortunately, just before the dome was built there was a theft. A gold olive branch left as a goodwill message was stolen, likely by a small floater bot. Since then this missing piece of Lunar history has grown in story, and is now known as Armstrong's Gold. The gold is worthless and perfect imitations can (and have - there is one inside the dome right now) be manufactured, but the symbolic meaning is powerful. It is worth a great deal to many people: many Lunarians would pay a fortune to get it or have it restored to its right place, collectors of historical memorabilia equally want it.
The only problem is finding it. Whoever got it is not talking.
Some think the treasure was in New Mumbai during the Fall and was either destroyed or is now protected by exsurgent horrors. A less radical theory is that the original thief was a bot jammer named Ronald Haahr, murdered in a criminal brawl before the Fall and not recovered since, but likely selling it to a wealthy collector. Some have suggested Kevin Pournelle, the nephew of noted gerontocrat Orson Pournelle, as a likely buyer. Kevin is known to be interested in space history (he owns several early satellites and spacecraft) and at one point tried to get the entire Apollo 15 site relocated to a space museum he wanted to build in Erato (this would incidentally have allowed one of his uncle's companies to exploit helium mining in the region). Another suspect is Dragomir Adamczyk, a Martian philanthropist and collector who also gathered historical objects. Some people think the olive branch lies in some souvenir drawer, unknown to its current owner.
Adventure possibilities:
An ego cache is found that contains a copy of Ronald Haahr. When restored, he might (willingly or not) point out his buyer... assuming he did the deed, and that he actually tells the true story. After all, why should a mythomaniac jammer displaced out of time not milk the situation to the utmost? And if he points out someone like Kevin Pournelle, how much chaos will it cause when the LLA brings its patriotism versus the might of the Pournelle family?
The reclusive Dragomir Adamczyk has become more reclusive over time, according to rumour due to a basilisk hack, nanovirus or incipient madness. His remote mansion in Syrtis Major is apparently uninhabited but for him, his AI staff and some defences. What treasures are in there?
The original suddenly resurfaces on Locus. Experts analysing the object attest to its authenticity. A criminal group is offering it for auction, with all sorts of unlikely contenders trying to buy or steal it. Why are the *Factors* trying to buy it?
(Another interesting "treasure" on Luna is the Fallen Astronaut Memorial on Hadley Rille. Although the memorial is tiny, it is one of the great symbols among the original space colonists.)
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Mea Culpa: My mode of speech can make others feel uninvited to argue or participate. This is the EXACT opposite of what I intend when I post.