The Falkirk wheel replaced locks in the Glasgow / Edinburgh canal. The thing is so efficient that it looses only a couple of pints of water a day (compared to thousands of gallons per passing boat before) Its so finely balanced that turning it uses practically no power (well less that boiling a kettle of water). Its also a bit of an attraction in its own right, its huge up close and certainly bizzare looking. (Great Simon by the way)