Monster Hunter.
Any locale with ruined buildings claimed by nature feels like it had some lore significance, but it's never expanded upon as far as I know.
There actually are a number of different lore books, and even some gear descriptions in-game, that all point to how there was an Ancient Civilization, from some thousands of years before the setting of the game, that indicates that humanity was once a) very technologically advanced and b) was very nearly wiped out because of their own hubris that came from disrespecting the natural order. The very reason weapons like the Gunlance, Switch Axe and Charge Blade exist in the current era of the MH games is because of the modern era of engineers and weapon-smiths being able to reverse-engineer that re-discovered tech so that your Hunter(s) can use them (even if they still don't understand entirely how it all works).
Even beyond that, the series has a number of things that still remain unexplained. Are Hunters, themselves, the descendants of some breed of dragon-hunting super soldiers from said Ancient Civilization? What kind of monstrosity left behind
the skeletal rib cage you can see in the Primal Forest (MH4/U, MHG/U)? And how much of the lore, some of it pretty nightmarish, described in some item/weapon/armor descriptions is true? Are there really some brand of assassins out there that will set out to kill Hunters if they are out of line with the Guild's rules? Is some evil voice whispering in your Hunter's ears destined to drive them mad once you don Fatalis Armor?
It's the kind of thing that makes the series' lore pretty interesting to ponder about, even if it's definitely not something that's at the series' forefront, or even something worth Souls-like levels of obsession.