Pontcysyllte aqueduct.
Pontcysyllte Aqueduct can be an alarming experience for any ship's captain!

Telford built a number of famous bridges - the Menai suspension bridge, for example, or the Conwy one - but his most notable one, in my opinion, was never opened for carriages or cars. It is the Pontcysyllte Aqueduct which carries the Shropshire Union canal over the River Dee.

The only way Telford could cross such a span was by using the new technology - cast iron; but he was not at all sure that it was up to the job. He therefore built a trial aqueduct in the middle of a field at Longdon, north-east of Shrewsbury, and when that worked, went for the full-size version a couple of miles east of Llangollen.

It really is an experience to stand beneath the Pontcysyllte aqueduct and look up to see narrow boats passing above your head, silhouetted against the blue sky! It is even more of an experience to be in the narrow boat; naturally, it was our luck to have a howling gale sweeping down the valley the day we hired a boat and cruised from Llangollen to Pontcysyllte and back again.

The wind was so strong that at one point in the six minute crossing it actually blew the camera and tripod over sideways, and water was splashed up over the lens of the second camera. The film is slow-paced, but so, believe me, is travelling by narrow boat!