Being an amateur when it comes to canal boats, it took more than a little courage to steer ours on to a 1,007ft (305 metre) long aqueduct, towering 126ft (39 metres) above a Welsh valley. The water channel was barely wider than our vessel and as I gripped the tiller tightly I noticed there was not even a railing between me and the sheer drop to the River Dee below. Imagine my horror when my daughter calmly called out: “It says in the guide book that the Pontcysyllte Aqueduct is nearly 200 years old and the masonry piers are hollow towards the top!”