Look, for example, at the following photo:
I believe the photo was taken in England, no doubt around the middle of last century (judging from the automobile in the background). But the only piece of solid information I have, concerning the subject of the photo, is a brief caption:
Testing the world's first rocket-propelled bicycle.
The fellow holding the handle bars seems to be about to straddle his machine, whereas the guy kneeling down behind the bike looks as if he's fiddling around with wires, or maybe lighting a match. Really, I'm as frustrated as hell. I would love to know what happened next.