In today's lecture, we'll discuss the history of the bicycle. Although early prototypes appeared in the 19th century, the first widely popular design was the penny-farthing, which had a large front wheel and a small rear wheel. However, it was quite dangerous because riders sat high above the ground. In 1885, John Kemp Starley introduced the 'safety bicycle,' which featured two equal-sized wheels and a chain drive. This design made cycling much safer and more accessible, leading to a cycling boom in the 1890s. Importantly, the safety bicycle also contributed to social change, as it gave women greater personal mobility and independence.