In today's lecture, we'll discuss the history of the bicycle. Although many people assume the bicycle was invented in the 19th century, its origins actually go back further. The first two-wheeled vehicle, called a 'running machine', was created by a German inventor in 1817. It had no pedals, and riders pushed their feet against the ground to move. Later, in the 1860s, pedals were added to the front wheel, but this design was unstable and difficult to ride. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular, which is the basis for modern bicycles.