The Foulridge Tunnel was a major construction achievement, but is today best known for the story of a cow who once swam the whole length of the tunnel. The tunnel is straight enough that you can see right through it, though the roof is quite low in places. Most of it was built using the 'cut and cover' method - but despite this, unexpectedly difficult rock conditions meant that construction took a whole six years. Travel through the tunnel, which has no towpath, is only possible in one direction at a time, so traffic lights control a ten-minute window in each direction each hour.
In 1912, a cow named Buttercup fell into the canal by the southern portal. Rather than wade out as usual, she chose to swim the whole 1640 yards to the northern end, where she was revived with brandy by drinkers in the nearby Hole in the Wall pub. Pictures in the pub commemorate the occasion.
Foulridge Wharf, also at the northern portal, was built to unload cargoes of raw cotton from North America for weaving in the Lancashire mills. There is a tea-room on the wharf as well as the pub. Foulridge Lower Reservoir, built to supply water to the canal, was constructed almost directly above the tunnel. The nearest town is Colne, two miles to the east, an ancient market town with a church dating back to the 11th century.