The Pontcysyllte Aqueduct, a 1,000-foot bridge that carries the Llangollen branch of the Shropshire Union Canal 116 feet (35 m) high across the valley of the River Dee, was designed by Thomas Telford, built between 1795 and 1805, and is one of the 'Wonders of the Waterways' in Britain's canal system. The canal system, covering 4,000 kms, was the highway network for the Industrial Revolution of the 18th and 19th centuries, and is now being restored to its full glory, for leisure use..