Today's lecture is about the history of the bicycle. The first bicycles, called velocipedes, appeared in the early 19th century and had no pedals. Riders pushed themselves along with their feet. In the 1860s, pedals were added to the front wheel, but these 'penny-farthings' were dangerous because the front wheel was very large. By the 1880s, the 'safety bicycle' with two equal-sized wheels and a chain drive was introduced, which made cycling much safer and more popular. Interestingly, this design is still the basis for modern bicycles.