More than 200 years later, this vast landmark was named a World Heritage Site.
The site starts at the Horseshoe Falls, named after the shape of the waterway the canal draws its stream from. Now you can follow in their footsteps, gazing at your reflection in the man-made weir where industrial design and natural beauty meet.
There are so many ways to enjoy this area: find out why visitors have spent more than a century forgetting their cares with short or longer horse-drawn boat trips along the canal wharf in Llangollen
Pulling on your walking boots
If you’d rather travel by foot than hoof and barge, there are 11 miles of countryside to soak up in this stunning corner of the country, all easily walkable with plenty of pubs and picnic spots as you go.
Intrepid walkers can head off track and onto trails such as the one between the Falls and Llangollen, which slopes down fields for a bracing, gentle wander in any season. There are loads of lengthier trails to choose from, not least the one along Offa's Dyke, the 8th century earthwork separating Wales and England.
This National Trust trail spans the entirety of Wales, but this bit of it might just be the best thanks to the Pontcysyllte Aqueduct itself.
Fancy crossing the 18 piers? Walk above it at sunset for spectacular views. Want to go underneath? Take a boat ride and admire the mortar under Britain’s largest aqueduct of its kind, said to have been made out of oxen blood, lime and water.
Then duck into Trevor Basin to park up or grab a drink and watch the canal conquerers breeze past.
There’s an expert local or two ready to captain a trip along the water if it floats your boat, but Trevor is neighboured by another village, Cefn Mawr. You’ll find a country park teeming with donkeys, chickens, pigs and other menagerie beauties there, as well as playgrounds and places to refresh.
Downstream, there’s another treat. Chirk Aqueduct is just as impressive as Pontcysyllte – perhaps unsurprising given that it was another triumph for Telford, built in 1801. A viaduct was added almost 50 years later, and crossing it takes you over the border to England. The magnificence of Edward I’s nearby Chirk Castle predates both, with local specialities taking in food, drink, gifts and crafts. Follow the River Dee, drop into the Ceiriog Valley and meet a few characters in the charming, historic village.
Lay back or go wild
Garden lovers shouldn't miss Plas Newydd with it's perfect lawns, brooks and glens built by a pair of Irish elopers. It’s not all peace and tranquility, though. The Llangollen Steam Railway hosts real ale rumbles and murder mysteries, the Llangollen International Eisteddfod is an annual celebration of dance and song – and if you’re after a headrush you’ll find rock climbing, white water-rafting, off-track adventuring, kayaking and much more.
Lay back or go wild – the choice is yours.