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. Later, in the 1860s, pedals were added to the front wheel, but riding was very uncomfortable because of the solid rubber tires. It wasn't until the 1880s that the safety bicycle, with two equal-sized wheels and a chain drive, became popular. Interestingly, the safety bicycle greatly increased women's mobility, as it allowed them to ride without wearing restrictive clothing. By the early 20th century, bicycles became a common mode of transport for workers.