The Pontcysyllte Aqueduct, designed by Thomas Telford is the highest canal aqueduct in the world. If you're not sure if you're scared of heights or susceptible to height vertigo, it's a good place to find out.

I got speaking to a lovely man walking his dog whilst recording this. He told me that the arches were built around bales of sheep wool to keep the weight of the 38 metre high arches down as well as hold the structure while building them. He also mentioned that lanolin, the waxy substance that keeps sheeps wool waterproof, was used to seal the canal. Doing some reading online, ox-blood was also used in the mortar to help prevent it crumbling away during freeze-thaw cycles. I'm not sure how many sheep were sheared and oxen bled for the constuction of the aqueduct, but imagining these 220 year-old animal materials impregnated throughout its structure didn't help much when walking back across it.

Anyway, in this recording you can hear blackbirds, flycatchers, thrushes, wrens and chiff chaffs, as well the occasional 'Morning!' as people walk or cycle by. There's also the occasional drip from the canal and the constant rumble of the River Dee below. We end with the sound of a narrowboat turning its engine back on after completing the 307 metre journey over the valley.

Recorded at 8am, Sunday 29th June.

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