In episode 4, Dannan caught up with Dougie from McFly, who nominated the bicycle into the Inventions Hall of Fame.
Here are some fun facts he learned along the way:
1. Early bicycles had the pedals directly attached to the front wheel, which had to be huge to give a high enough gear to go anywhere. Hence the classic penny-farthing design.
2. The chain and sprocket drive was the big breakthrough, with the Rover Safety Bicycle, allowing the pedalling effort to be geared up and hence sensible progress to be made with a smaller wheel. The Rover Safety was the first 'modern' bike.
3. Bicycles are ridiculously efficient - up to about 99% of the energy you put in goes to propelling you forwards. Which is more efficient than walking. They're by far the most efficient forms of transport, and right up at the top of any list of "most efficient machine".