Deep in the Sahara desert is the world's longest conveyor belt system. I went to see this king of conveyors, to find out why it was built, only to discover how its story is deeply intertwined with an international border dispute... CREDITS Original map of Morocco Protectorate by Cradel (adaptations are my own work) - https://commons.wikimedia.org/wiki/Ca... Phosphate stats from US Geological Survey - https://www.usgs.gov/centers/nmic/pho... Map music from the Map Men series by Jay Foreman - https://www.youtube.com/playlist?list...