This video explains why the popular book “1421: The Year China Discovered the World” should not be considered to be legitimate history.  The book claims that in the year 1421 Chinese expeditions sailed completely around the world (including even exploring the northern Arctic passage) decades before Columbus even discovered America, and it also claims that the Chinese established colonies in America.  The video explains that the book was not fact checked, it relies on suppositions, it doesn’t cite proper sources, and it makes use of dubious “replications” of maps.