The River Severn is the longest river in Great Britain. It is 354 km long. The Severn separates Wales from England. There are several waterfalls at the source of the river. They are not very high or powerful. However, lots of people go there to take photos of the wonderful waterfalls. Then the Severn runs though green hills and beautiful valleys. There are many old towns and modern cities on the banks of the Severn. In summer, many tourists cycle along the river and explore the countryside. On the one hand, travelling by bike is very exciting but, on the other hand, it can be rather dangerous and difficult.