The reason why Iran has such sway over fossil fuels has to do with a quirk of geology. The country sits on top of where the Arabian tectonic plate is smashing into the Eurasian plate. This continental collision gave rise to the Zagros Mountains, which push down on the Arabian plate in a way that has created a basin in Earth’s crust that traps hydrocarbons—hence, all that oil and gas. The region contains about 12 percent of the world’s oil, according to one 2024 estimate.