Pontcysyllte Aqueduct

The Pontcysyllte Aqueduct is Thomas Telford's masterpiece - a slender cast-iron trough carrying the Llangollen Canal thirty-eight metres above the River Dee on eighteen tall stone piers, and a genuinely spectacular subject from the air. It is a UNESCO World Heritage Site near Trevor, with the wooded Dee valley falling away beneath and narrowboats and walkers crossing the vertiginous towpath. For flyers this is a honeypot and needs care. The land around the aqueduct and basin is managed by the Canal and River Trust, which restricts taking off and landing from its property without permission, so do not launch from the towpath or basin - use public ground away from the structure and photograph it from a distance. It is a busy, popular place, especially at weekends, so people below the flight path are a constant consideration; keep well clear of the towpath crossings and the moored boats. There are no airfield flight restrictions nearby - Hawarden lies well to the north-east. The valley is steep and can be gusty, and the aqueduct's height means a long drop, so fly conservatively. Early on a weekday morning, when the site is quiet and mist sometimes hangs in the Dee valley, gives the cleanest shot of the piers marching across the gorge.