Not once, not twice, but eight different times has Popular Science or Popular Mechanics magazine declared that the future of travel is the monowheel. Wesley Treat collected the covers of these issues for a retrospective spanning from 1914 to 2007. The "One-Man War Tank" shown is from 1933. Most impressive is that you could buy a magazine for fifteen cents! Link -Thanks, beth!
15cents was three loafs of bread back then. That would be somewhere around $5-$6 now.
...helps to keep things in perspective.