Llangollen and Pontcysyllte

The canal boat leaves the ground. At Pontcysyllte, a few miles down the Dee from Llangollen in Denbighshire, north-east Wales, the Llangollen Canal crosses the whole valley in an iron trough on nineteen stone piers, 38 metres above the river, with a towpath on one side and nothing at all on the other. Thomas Telford and William Jessop built it between 1795 and 1808, and boats have been floating over the treetops ever since.

UNESCO inscribed the aqueduct and eleven miles of the canal in 2009 as a masterpiece of the Industrial Revolution's heroic phase, the first great work of Telford's career; it was the tallest navigable aqueduct in the world for two centuries, and you can walk the towpath across it for nothing or cross by boat from Llangollen Wharf, where horses have been towing passenger boats along the canal for well over a hundred years. Llangollen itself is an old inland resort under a conical hill, with the ruins of Castell Dinas Brân, a native Welsh castle of the thirteenth century, on the summit; its stone bridge over the Dee makes the traditional list of Wales's Seven Wonders, the river beneath it, once worked by coracle fishermen for salmon, is now white water for kayaks and rafts, and the 1865 station across the bridge is the home of a steam railway that runs ten miles up the Dee valley to Corwen. The town's International Musical Eisteddfod has brought choirs from across the world to a pavilion in the meadows every summer since the war, and the Horseshoe Falls, Telford's weir that feeds the whole canal, lies a short walk upstream.