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. It was called a 'hobby horse'. Later, in the 1860s, pedals were added to the front wheel, creating the 'velocipede'. However, this design was uncomfortable because of the rigid frame and iron wheels. The 'penny-farthing', with a large front wheel and small rear wheel, became popular in the 1870s, but it was dangerous due to its height. Finally, the 'safety bicycle' with two equal-sized wheels and a chain drive was introduced in the 1880s, making cycling much safer and more accessible to the general public.