In today's lecture, we'll discuss the history of the bicycle. The first bicycle, invented in the early 19th century, had no pedals; riders pushed their feet against the ground. This was called a 'hobby horse.' Later, in the 1860s, pedals were added to the front wheel, creating the 'penny-farthing.' However, these were dangerous due to their large front wheel. It wasn't until the 1880s that the 'safety bicycle' appeared, with two equal-sized wheels and a chain drive, making it much safer and more practical for everyday use.