Heading back to the Welsh Border we stopped to walk over the Pontcysyllte Aqueduct on the Llangollen Canal, built by Thomas Telford and opened in 1805. The aqueduct carries the canal over a valley is an iron trough. Walking along the towpath you have a secure fence on one side, and the canal on the other. In a boat, on one side you just have a strip less than 6 inches wide, the edge of the iron trough, between you and a 126 foot drop to the river below.
