Bristol grew wealthy on trade through its harbour. Yet for centuries strong tides left vessels half buried in mud at low water. The problem was solved in the early 19th century, when a stretch of the River Avon was enclosed to create a deep water pool. Since the commercial docks moved to Avonmouth, the Floating Harbour has been transformed into a leisure marina. It is thronged each year for the Bristol Harbour Festival. Tall ships visit for the colourful event.