How’s that for topical?
I remember my first exposure to the Loremaster Series (Iron Wind and Cloudlords). One aspect that made an impression on me was the barrier aspect to the “Essence Flow”–magical currents that also acted as real physical barriers. This was more pronounced in Cloudlords where Tanara was physically isolated from other parts of Jaiman and featured very different and unique cultures. The underground, goth Duranaki, the Viking like Muri, the Inca style Yinka, the rural, gentle Suline and the Roman/heroic cloudlords. Pretty unique and cool!