Today's lecture is about the history of the bicycle. The first bicycle, invented in the early 19th century, had no pedals and was pushed along by the rider's feet. Later, in the 1860s, pedals were added to the front wheel, but this design was unstable because the wheel was very large. It wasn't until the 1880s that the 'safety bicycle' with two equal-sized wheels and a chain drive became popular. This design made cycling much safer and more accessible, especially for women, who began to use bicycles as a means of independent transport.