Qanats ( https://en.wikipedia.org/wiki/Qanat ) are really funky things. The wikipedia article also features this striking satellite pic of southern Iran: https://en.wikipedia.org/wiki/Qanat#/media/File:Alluvial_fan_in_Iran.jpg . A fan of green in an arid landscape. What I didn't know, before reading up about them recently, is that you can get to near freezing temperatures with those things and do things like keeping ice around over the summer. In a desert.
I quite like these disgressions, "Kouya ni Kemono Doukokusu" ( https://mangadex.org/title/1027/kouya-ni-kemono-doukokusu ) has similar digressions about cool bits of geographical and cultural trivia. A recent chapter had a digression about cenotes. Ties in well with the qanat topic since cenotes ( https://en.wikipedia.org/wiki/Cenote ) were one of the main perennial large fresh water sources for the Inca in the Yucatan peninsula. The manga also calls out a really crazy thing I wasn't aware of, namely that the distribution of cenotes in the northern bit of the peninsula is very much shaped by the Chicxulub crater from the impact that wiped out the dinosaurs.