Gleaming silver and 520 metres across, the Thames Barrier has been variously called a triumph of modern engineering and the eighth wonder of the world. It's certainly one of the capital’s most dramatic landmarks. The shiny silver fins, lined up across Woolwich Reach, are indeed an impressive sight. Built in 1982 at a cost of £53million, the Thames Barrier has already saved London from flooding some 80 times. It is regularly in action for maintenance purposes – the website has a current timetable. The Thames Barrier Information Centre is on the south side of the river and boasts an interactive model of the barrier and an eight-minute video about its construction, as well as close-up views of the real thing along with a pleasant café with riverside picnic benches. The north end of the Thames Barrier sits adjacent to the Thames Barrier Park.