newsfromlondon201110

The Thames Barrier is the world's second-largest movable flood barriers in the world (after the Oosterscheldekering in the Netherlands). It spans 520 metres across the River Thames near Woolwich, and it protects and prevent the 125 square kilometres of central London from being flooded, caused by tidal surges. It became operational in 1982 and has 10 steel gates that can be raised into position across the River Thames. When raised, the main gates stand as high as a five-storey building and as wide as the opening of Tower Bridge. Each main gate weighs 3,300 tonnes.