Cardiff Bay was a natural inlet of the Bristol Channel. Prior to the 1980s, the waterway called Tiger Bay was mostly used for shipping docks. However, at low tide it became an ugly, unnavigable mudflat. In 2001, the 3,600 foot long Cardiff Bay Barrage was built as a dam to control water levels. The resulting 500 acre, freshwater lake was renamed Cardiff Bay. This success led to a complete transformation of the northern shoreline. On the right is the distinctive Pierhead Building.