Christopher Columbus is sure that the world is as round as his head. The King insists that it’s as flat as Columbus’ head (which he flattens). Bugs, a ship’s mascot, helps Columbus demonstrate the planet’s roundness by tossing a baseball, which comes back from the other direction, covered with travel stickers (making better use of the sole good gag in the 1939 Looney Tune Kristopher Kolumbus Jr.
