I always take the celebration of Columbus Day as a relatively minor example of the stupidity of people. The only things that Columbus discovered were that the riches of Asia were a lot further away than he thought and there was also no easy way to get there by sailing straight west from Europe into the setting sun. I guess I can give him credit though for proving, at least to some sentient humans, that the world is not flat and you won't sail off the edge if you are brave enough to embrace the future and sail forth. That would leave out Republicans, of course.
The latest evidence indicates that the first groups of human beings to arrive in the Americas were here roughly 30,000 years ago. Unless you have been homeschooled by Christian fanatics, you can do the math and come to realize that that would place the first discovery of America way before 1492. Even shortly before the arrival of Columbus, there's plenty of evidence that sailors from other places beat Columbus to America. As most of us know, the Vikings, led by Leif Erikson got to the New World in 985. Then there's the matter of evidence and legends that Phonecians, West Africans, Chinese, and even prehistoric Iberian Salutreans all got here even before the Vikings and certainly before Columbus. Genome mapping projects of Polynesians and indiginous South Americans indicate a cross sea connection back as far as the year 1200 or further. In some cases, the people mentioned may have gotten here way, way, way before. In short, the way I've always seen it is that Columbus was "the last man to discover America." I always say that humanity set sail for places unknown as soon as some group of people figured out how to tie enough logs together to build a raft or taught themselves how to construct a viable large canoe and carry enough drinking water for a long trip or island hopping. Some even walked here 15,000 years before there was even a Spanish royal family that Columbus could ask for financing to build his ships. So folks, Happy Native American Day!