The issue of "Who discovered America?" is absurd. Not only that, but dating the "discovery" at 1492 or even 1000 AD is crazy.
There was massive sea travel not only from Europe to the Americas by the Norsemen and Irish (among others), but also from Africa, Asia, and Polynesia.
There's ample evidence that this took place not one thousand years ago, but thousands of years ago.
Why isn't this taught in school?
Because the Vatican, in order to bolster its claim to and ownership of the Americas, claimed that the Americas was populated by people who walked across a Bering Sea land bridge. Ever since all the "bought and sold" scientists in the world have repeated that absurd lie.
There are no Native American myths about people crossing the Bering Strait to get to America. None, zero, nada. Nowhere.
"In myth all the founding gods of great civilizations were navigators" - "Atlantis in America"