The latest of The Oatmeal makes a pretty compelling case for hating Christopher Columbus, whose achievements ("discovering" America, sailing from Europe to America, proving the curvature of the Earth) are all BS. More importantly, though, is what Columbus did do: launched a campaign of genocide in order to terrorize indigenous people gold-mining slavery, a program buoyed up by mass slaughter, mutilations, and systematic sexual slavery of girls as young as nine or ten.
Matthew Inman, the Oatmeal's author, proposes celebrating the life of Barolome de las Casas, who also set out to slave and murder his way through the New World, but changed his mind, took the cloth, and spent 50 years defending indigenous people. That's a nice idea, but if we're going to celebrate the struggle of indigenous people against genocide and slavery, maybe the right people to celebrate are the indigenous heroes and victims of Europeans, not Europeans who thought better of the unconscionable, no matter how thoroughly they repented.
Inman cites Howard Zinn's excellent People's History of the United States as a primary reference for the piece, and I concur: Zinn's work and those derived from it (like the graphic novel and the audio of dramatic readings) are important and fantastic works.