I read this article some time ago about Christopher Columbus that debunks all the popular myths about him being a hero and why the myths came into being also. And Columbus Day is not an American tradition, but a "recent mistake." It also talks about a much better person not well known about who the writer of the article believes should have received the recognition of a hero instead of Columbus.
Christopher Columbus Was Awful (But this other guy was not)
Christopher Columbus Was Awful (But this other guy was not)