Columbus

The mistaken idea that Columbus proved the Earth is round is listed among the top 20 history myths:

"It was American author Washington Irving, some 500 years after Columbus sailed to America, who first portrayed the Italian explorer as launching on his voyage to prove that the Earth was round, defying the common, flat-earther belief of the time. In fact, most educated Europeans in Columbus's day knew that the world was round. Since the fourth century BC, almost nobody has believed that the Earth is flat. Even if that wasn't the case, Columbus would never have set out to prove that the Earth was round... simply because he didn't believe it himself! Columbus thought that the Earth was pear-shaped. He set sail to prove something else: that Asia was much closer than anyone thought. Even in this, he was wrong. To further besmirch his memory, it should also be noted that he never set foot on mainland America. The closest he came was the Bahamas. Pear-shaped, indeed!"