The Llangollen branch of the Shropshire Union Canal must be one of the most spectacular and scenic canals in Britain. The canal is fed from the River Dee at the Horseshoe Falls just out of Llangollen. You can walk through Darkie Tunnel but beware it is some 1200 feet in length, so a flashlight is recommended, it is one of two tunnels at Chirk, the other is the shorter Whitehurst Tunnel.

A quote in "the Life of Thomas Telford" publication says "...Aqueduct is situated in a finely wooded valley, having Chirk Castle as an eminence immediately above it, with the Welsh Mountains and Glen Ceiriog as a background and the village of Chirk with Lord Dungannon's Ceiriog Bridge occupying the intermediate space. These combined objects compose a landscape seldom surpassed."

The 70 feet high aqueduct built between 1796 and 1801 by Thomas Telford and William Jessop was built, like the Pontcysyllte, to carry the Ellesmere Canal.