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 due to its rigid frame. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular. Interestingly, this design significantly reduced accidents, which is why it was called 'safety.' Today, modern bicycles have evolved with lightweight materials and advanced gear systems.