According to the 1421 hypothesis, between 1421 and 1423, during the Ming Dynasty of China, a fleet of Chinese ships traveled to many parts of the world unknown to contemporary Europe, including Australia, New Zealand, the Americas, Antarctica, Greenland, and the Northeast Passage. The hypothesis is allegedly based on evidence from shipwrecks, old maps, Chinese documents, and accounts by navigators such as Christopher Columbus. Why have professional historians largely dismissed this hypothesis? Discuss
Source: The Free Dictionary