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. Later, the penny-farthing, with a large front wheel, became popular but was dangerous. In 1885, the safety bicycle was introduced, featuring two equal-sized wheels and a chain drive, making it much safer and more practical. This design quickly replaced earlier models and laid the foundation for modern bicycles.