3649147 Pont-y-Casullte Aqueduct, in the Vale of Llangollen, Denbighshire (engraving) by English School, (19th century); Private Collection; (add.info.: Pont-y-Casullte Aqueduct, in the Vale of Llangollen, Denbighshire. This aqueduct 1007 feet in length, carries the waters of the Ellesmere Canal over the River Dee. Illustration for Curiosities of Great Britain by Thomas Dugdale (L Tallis, c 1850).); by Look and Learn.