Giant George, a 43-inch-tall Great Dane from Tucson, Ariz., holds two world records: tallest living dog and tallest dog ever. This gentle giant has a developed quite the fan base so his owner, David Nasser, keeps fans up to date with the dog’s activities via his website and YouTube channel. Giant George also has a book, "Giant George: Life With The World's Biggest Dog," which was published by Simon & Schuster.