When you think of a potato, one state probably comes to mind: Idaho. But for much of American history, Maine was home to the nation's largest potato crop. That status had changed by the 1970s, with the West growing more and more of the nation's potatoes. But Maine still had one distinct advantage: A privileged position in the commodities market. The New York Mercantile Exchange, one of the largest such marketplaces in the country, exclusively dealt in Maine potatoes. And two deep-pocketed Western potato kingpins weren't happy about it. So the Westerners waged what's now called the Maine Potato War of 1976. Their battlefield was the futures market: A special type of marketplace, made up of hordes of screaming traders, where potatoes can be bought and sold before they're even planted. The Westerners did something so bold – and so unexpected – that it brought not only the potato market, but the entire New York commodities exchange, to its knees. Today on the show, how a war waged through futures contracts influenced the kind of potatoes we eat. This episode was hosted by Dylan Sloan and Nick Fountain. This episode was produced by Sam Yellowhorse Kesler with help from Emma Peaslee. It was edited by Molly Messick, engineered by Valentina Rodríguez Sánchez, and fact checked by Sierra Juarez. Our executive producer is Alex Goldmark. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Picture the Pacific Ocean of the 16th century. Spanish Galleons sail the wide open seas, carrying precious cargo like silver, porcelain, and textiles. The waters are dangerous; ship logs show concerns over pirates. But pirates are not to blame for a mysterious event that keeps happening. For, you see, one in five of the ships leaving from the port of Manila didn't make it to Acapulco. It's a shipwrecking rate much higher than rates for other routes of the time. And the mystery of the serial shipwrecking Spanish ships remains unsolved, until today. Everyone involved with these Spanish ships were aligned in a goal: Don't wreck the Spanish ships. And yet, wreck they did. Three economists took a look at the incentives for profit and risk at the time, and found the key to unlocking this ancient booty (of knowledge). Our show today was produced by James Sneed, edited by Jess Jiang, fact-checked by Sierra Juarez, and engineered by Cena Loffredo. Alex Goldmark is Planet Money's executive producer. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy