The River Severn is the longest river in the United Kingdom, spanning a length of approximately 354 kilometers (220 miles). It rises in the Cambrian Mountains of Wales and flows through England, eventually reaching the Bristol Channel. The river is known for its tidal bore, a natural phenomenon where a wave-like surge of water travels upstream against the current. The River Severn has played a significant role in the country's history, serving as a trade route and a source of water for various industries.