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.