Lined with important national institutions, Cardiff Bay is where the modern Welsh nation is put on display in an architect's playground of interesting buildings, large open spaces and public art. It wasn't always this way. By 1913 more than 13 million tonnes of coal was being shipped from Cardiff's docks. Following the post-WWI slump the docklands deteriorated into a wasteland of empty basins, cut off from the city by the railway embankment. The bay outside the docks – which has one of the highest tidal ranges in the world (more than 12m between high and low water) – was ringed for up to 14 hours a day by smelly, sewage-contaminated mudflats.
Since 1987 the area has been completely redeveloped. The turning point came with the erection of a state-of-the-art tidal barrage, completed in 1999, which transformed the mudflats into a freshwater lake by containing the waters at the mouth of the Rivers Taff and Ely. It was a controversial project, as its construction flooded 490 acres of intertidal mudflats which, despite their unpleasant aspects, were an important habitat for waterfowl. The barrage includes sluice gates to control the water flow, three lock gates to allow passage for boats, and a fish pass that lets migrating salmon and sea trout pass between the river and the sea.
Cardiff Bay's main commercial centre is Mermaid Quay , packed with bars, restaurants and shops. To its east is Roald Dahl Plass , a large public space (it used to be a dock basin), named after the Cardiff-born writer, that serves as an open-air performance area, overseen by a soaring, stainless-steel water sculpture .
