The Laxey Wheel, known as 'Lady Isabella', is the largest surviving original working waterwheel in the world, built in 1854 to a design by mining engineer Robert Casement. It was constructed to pump water from the Glen Mooar section of the Great Laxey Mines, a lead- and zinc-mining operation, at a time when the Isle of Man had no coal supply to power steam alternatives. The wheel takes its name from Lady Isabella, wife of then-Lieutenant Governor Charles Hope. With a diameter of 72 feet 6 inches and a backshot design, it remains a landmark of Victorian mining engineering. Maintained today by Manx National Heritage, the wheel appears on the reverse of the Isle of Man £20 banknote.