Today we're going to discuss the history of the bicycle. As you know, the modern bicycle has two wheels of equal size, but early versions were quite different. In 1817, a German inventor created a wooden frame with two wheels, but the rider pushed along the ground with their feet. This was called a 'hobby horse'. Then, in the 1860s, pedals were added to the front wheel, making the 'penny-farthing' popular, which had a very large front wheel and a small rear wheel. However, this design was dangerous because riders could easily fall forward. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels was introduced, which is the basis for modern bicycles.