The Incredible Story of the US Army’s Earth-Shaking, Off-Road Land Trains - https://getpocket.com/explore/item/the-incredible-story-of-the-us-army-s-earth-shaking-off-road-land-trains

Why the Aztecs, Inca, and Maya never invented the wheel - https://bigthinkmedia.substack.com/p/why-the-aztecs-inca-and-maya-never