Bicycles have a long and remarkable history that started in the early nineteenth century. The first bicycle-like machine had no pedals, so riders had to push it with their feet, which made travelling slow and uncomfortable. Later inventors introduced metal frames, rubber tyres and safer steering systems. As a result, bicycles quickly became a popular means of transport in many countries. Today cycling is considered an environmentally friendly activity because it produces no pollution and helps reduce traffic in crowded cities. Moreover, doctors say that regular cycling improves coordination and strengthens the heart. Many modern cities now build special lanes to make cycling safer for both children and adults. Although bicycles have changed a lot, they remain simple, efficient and enjoyable to use.