Tower Bridge is 800 feet long has a space 28 feet when closed but opens in the center until it reaches 140 feet that allow ships sailing on the Thames. On days when more goods are often moved by sea rather than air, the bridge is raised about 50 times each day.
Tower Bridge using the 432 workers who built it for 8 years. At that time they sank 70,000 tons of concrete into two big piers, placing second supporting structure into place, each weighing 1,000 tons and decorate the entire bridge with Portland stone and Cornish granite to cover the 11,000 tonnes of iron underneath.
