For two and a half centuries, from 1565 to 1815, Spanish galleons crossed the Pacific between Manila and Acapulco, linking Asia, the Americas, and Europe in the first truly global silver trade. This episode traces how Andres de Urdaneta cracked the seemingly impossible eastbound return route by sailing far north to catch the Kuroshio current, how the ships themselves were built in Philippine shipyards from cannonball-deflecting hardwood and abaca rigging, and why crews of press-ganged Filipino sailors routinely died of scurvy on six-month crossings while the holds were stuffed with silk, porcelain, and spices.

The economic engine was pure arbitrage: silver from Potosi and Mexico bought roughly twice as much in Ming China, where the Single Whip Law demanded taxes be paid in bullion. Profit margins of 300 to 400 percent led merchants to overl ...