Walking along a calm canal as the autumn leaves fall is an  idyllic way to spend an afternoon. And the Llangollen canal in Wales is the perfect place to make that a stunning reality. 

However, there is one part of it dubbed the “stream in the sky,” as it is part of the UK’s highest aqueducts, the second-highest in the world, and is not for the faint-hearted. The Pontcysyllte Aqueduct is 39m (127ft) high, has 19 arches, is around 3.6m (12ft wide) with a path and canal and is a World Heritage Site. It is completely free to walk across, or you can pay to take boat tours or canoes across for the most breathtaking views of the valley below.

But, it comes with a safety warning. Before stepping foot on the bridge, the signage warns you to keep hold of children as the bars on the aqueduct are quite far apart. 

I have visited the Pontcysyllte Aqueduct (pronounced pont – ker – sulth – tay) a couple of times before, always in autumn. And I am always in awe at this marvel of engineering. But I am also gripping onto my five-year-old for dear life. 

With a canal on one side and a sheer drop of 39m on the other side, it can be terrifying if you think about it too hard. And it gets even more congested if you have to pass people coming from the other direction. 

It is so immense, I have never actually made it across to the other side, I have always had to turn back with my little one.

But the views of the Welsh valley below are stunning, which is what keeps me coming back.

Built from cast iron and stone, the aqueduct was completed in 1805 by the canal company’s general agent (like a general manager today), Thomas Telford, and the consulting engineer was William Jessop.

John Simpson built the stonework of Pontcysyllte (and nearby Chirk Aqueduct), while William Hazledine provided the ironwork. It was built as part of the industrial waterway linking the River Severn at Shrewsbury and the Port of Liverpool on the River Mersey, although the canal system was never fully completed or realised due to costs.

The aqueduct was used to carry boats of coal and limestone and was in commercial use until 1936.

The Pontcysyllte website said: “The Pontcysyllte Aqueduct and Canal was inscribed as a World Heritage Site in 2009, as a ‘masterpiece of creative genius’.

“Thomas Telford’s innovative handling of a difficult geographical setting, using bold engineering solutions, has served as an inspiration for other projects all over the world since the early 19th century.”

Today, the aqueduct is used for leisure activities with a number of narrow boat cruises and canoe adventures along the canal waterways.

There is a large car park, which has a flat rate of £3. There are public toilets and access to a visitor centre and shop on the other side of the canal. 

There are also plenty of cosy pubs to head for lunch as well as places to explore nearby, such as the Llangollen steam railway in the town itself.

You can also visit Horseshoe Falls, another water feature built as part of the Llangollen waterways system and Chirk Viaduct and Cefn Viaduct.

Find out more on the Pontcysyllte Aqueduct website here.