Good morning, everyone. Today we're going to discuss the history of the bicycle. Now, many people think the bicycle was invented in the 19th century, but actually, the first two-wheeled vehicle appeared in 1817, invented by a German baron named Karl von Drais. However, it had no pedals; riders pushed their feet against the ground to move. It wasn't until 1860s that pedals were added to the front wheel, creating the 'boneshaker'. Then in 1885, the 'safety bicycle' was introduced with a chain drive and equal-sized wheels, which became popular because it was much safer than earlier models. So, the key innovation that made cycling widely accessible was the chain drive system.