I hope the folks who are driving all this do not mind that I don't care if he was an Italian, a Spaniard, or a Martian for that matter. I am rather more interested in what he accomplished, and how he effected history.
Martian? I don't think anyone is suggesting that Christopher Columbus was Martian, although there's a strong body of evidence linking Columbus with the Red Planet, in particular E.E."Doc" Smtih who popularized the idea of Christopher Columbus as a Martian Aboriginal in his "Lensman" series of pulp fiction novels. Also look into a less-strong but almost equally compelling body of evidence in the works of Richard Hoaglund, casting Christopher Columbus as a Hyperdimensional Fraud of the first order, a stalking horse for the Isis Society and Madame Blavatsky's Wicked Pack of Cards.