“The aqueduct [on the Llangollen Canal] was built by Thomas Telford and William Jessop, is 1,007 ft (307 m) long, 11 ft (3.4 m) wide and 5.25 ft (1.60 m) deep. It consists of a cast iron trough supported 126 ft (38 m) above the river on iron arched ribs carried on nineteen hollow masonry piers (pillars). Each span is 53 ft (16 m) wide. Despite considerable public scepticism, Telford was confident the construction method would work. … it was one of the first major feats of civil engineering undertaken by Telford, by then a leading civil engineer, supervised by Jessop, the more experienced canal engineer. The iron was supplied by William Hazledine from his foundries at Shrewsbury and nearby Cefn Mawr. It was opened on 26 November 1805, having taken around ten years to design and build at a total cost of £47,000 (£2,930,000 as of 2011).” It was given status as a World Heritage Site in June 2009. There is a fuller entry see
http://en.wikipedia.org/wiki/Pontcysyllte_Aqueduct
