> A 'safety' bicycle is what you and I think of as a bicycle with two wheels that are the same size and a chain drive. Bicycles before that would refer to penny-farthings and chainless devices too - that's how ubiquitous the 'safety' bicycle became, we don't even know of the other versions as bicycles today.

What I don't understand about this history is why anyone ever thought the penny-farthing design was a good idea.

It was before anyone thought to apply gearing with a chain.

The pedals directly turned the wheel, and a larger wheel got you more distance per turn. If you've ever watched someone on a unicycle you can see how much effort a small chain-less wheel requires.