The Pontcysyllte Aqueduct (Welsh pronunciation: [ˌpɔntkəˈsəɬtɛ], full name in Welsh: Traphont Ddŵr Pontcysyllte) is a navigable aqueduct that carries the Llangollen Canal across the River Dee in north east Wales. The 18-arched stone and cast iron structure, which took ten years to design and build, was completed in 1805. It is now the oldest and longest navigable aqueduct in Great Britain and the highest in the world.
The aqueduct was to be a key part of the central section of the proposed Ellesmere Canal, an industrial waterway that would create a commercial link between the River Severn at Shrewsbury and the Port of Liverpool on the River Mersey. However, only parts of the canal route were completed because the expected revenues required to complete the entire project were never generated. Most major work ceased after the completion of the Pontcysyllte Aqueduct in 1805. Although a cheaper construction course was surveyed further to the east, the westerly high-ground route across the Vale of Llangollen was preferred because it would have taken the canal through the mineral-rich coalfields of North East Wales.
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