I have trouble following what you mean here, but a story of something I did that might be in that direction:
I am recalling a bit from a #Traveller game I ran a few years back. The PCs were up to something else on a planet, but the Ancients Hunter PC of course scanned the planet for Ancient ruins. On the fly I declared there was a huge water-filled crater named “The Warscar” which the locals claimed was a relic from the Ancients War.
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