These kind of discussions always come up, and in terms of ‘who discovered America’ it gets to be all muddied and a mess. The Vikings most assuredly did reach the New World, that is not in dispute, though you also could point out that in the end had little to no lasting impact.
More importantly, the standard party line about the “native Americans” being the original settlers has come into doubt, the whole land bridge from Siberia migration about 10,000 years ago may very well have been one of many migrations, there is evidence coming up that there may have been earlier settlers. Explorers from Europe might have come over thousands of years ago, when the ice floes were still in place, skirting the ice to make the trip from what is now Europe.
If there were earlier native settlers, it is also possible that the later migrants, the forbears of current Native Americans, killed them.
And Columbus certainly wasn’t the first European to ‘find’ the New World, the Basque were fishing off the grand banks and were salting down cod on what is new Newfoundland many hundreds of years before Columbus’ voyage, it might have been as early as the 12th century. Thing was, the Basque were smart, because they had a pretty good monopoly on cod in Europe, local stocks had been depleted, so they made pretty good money fishing the Grand Banks by themselves, so why would they tell anyone?
There is no doubt that Columbus has been romanticized, but so have native populations, too. Should we celebrate the Aztecs, who committed human sacrifice and were responsible for wiping out whole populations of people? Should we celebrate the native american tribes in North America who were warlike and spent a lot of time killing other tribes?
I am not saying Columbus was a great person we should celebrate, I am saying that you have to be very careful when creating a saint, as they did with Columbus and with other historical figures associated with the ‘founding’ of the US and the New World, but it also is dangerous to try and turn any human beings into Saints. Columbus was not alone in cruelty, the legacy of the Spanish Conquistadores in South America was not exactly pure, and there were plenty of sinners, including the Catholic Church who aggressively set out to destroy native cultures in the New World, and who while at times tried to balance out the horrors inflicted on native people, like forced labor in the mines that killed many 10’s of thousands, also quite willingly accepted the very silver and gold that those people had mined. Columbus voyage did spur other explorers, there is no doubt, and in that sense it did lead to the colonization that led to the US being founded (among other things, Columbus basically lied a great deal of what he saw, he exaggerated things which of course triggered the greed motive). I would much prefer that maybe we have a day when we actually talk honestly about things, whether it is Columbus or those who quite frankly mythologize what the Native Americans were as people or groups of people, human beings can do amazing things and also can make the name human being something to be whispered about, not to be mentioned in polite society.
As far as the earth being flat, that is very much a myth, while no doubt there were people who believed that still when Columbus sailed, given the ignorance that was still very common, it was not widely believed and Columbus certainly knew it wasn’t. Among other things, by that time Ancient Greek texts were coming into Europe and they had the writings of Eratosthenes who calculated the circumference of the Earth 200 years before Christ, not to mention observations being made at the time. Still, there was a lot of fear and ignorance in the world, and if you look at the size of the ships they were sailing on (they were tiny), and how rough and dangerous deep ocean voyages are, it still took people either crazy enough, or greedy enough, or just plain brave enough, to undertake those kind of trips, if they didn’t believe the earth was flat and they would go off the edge, they didn’t really know what was going to happen to them, either, when they sailed west, and while there may not have been sea monsters, there were terrible storms, fear of starvation, lack of water, and any number of things that could kill them, including reefs and the real villain of ships of the time, the shipworm, that could riddle the hull and make it leak.