On March 8, 1421, the largest fleet the world had ever seen sailed from its base in China. The ships, huge junks nearly five hundred feet long and built from the finest teak, were under the command of Emperor Zhu Di's loyal eunuch admirals. Their mission was 'to proceed all the way to the end of the earth to collect tribute from the barbarians beyond the seas' and unite the whole world in Confucian harmony. Their journey would last more than two years and circle the globe. When they returned in October 1423, the emperor had fallen, leaving China in political and economic chaos. The great ships, now considered frivolous, were left to rot at their moorings and the records of their journeys were destroyed. Lost in China's long, self-imposed isolation that followed was the knowledge that Chinese ships had reached America seventy years before Columbus and circumnavigated the globe a century before Magellan. Also concealed were how the Chinese colonized America before the Europeans and transplanted to America, Australia, New Zealand and South America the principal economic crops that have fed and clothed the world.