Dynasphere
The Dynasphere was a monowheel electric vehicle invented in 1932 by Dr. J. A. Purves from Taunton, Somerset, UK. It had 2.5 horse power and once attained a speed of 25mph.

The Dynasphere was a monowheel electric vehicle invented in 1932 by Dr. J. A. Purves from Taunton, Somerset, UK. It had 2.5 horse power and once attained a speed of 25mph.
They left out telling you that the 25mph was when, out of control, it careered off a cliff.