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Location: Lancashire County and Manchester, England
Completion Date: 1776
Length: 274,560 feet (52 miles)
Engineer(s): John Gilbert, James Brindley
Beneath the old county of Lancashire, England, lie miles and miles of underground canal -- 52 to be exact. Considered an engineering masterpiece of the 18th century, the "Navigable Level," as it was known in its day, serves as a monument to the area’s industrial past.
Francis Egerton, the third Duke of Bridgewater, wanted a canal to transport coal from his mines at Worsley to Manchester, a distance of 10 miles. He commissioned John Gilbert and James Brindley to build the Bridgewater Canal, a gravity-flow canal crossing the Irwell valley on an elevated structure supported by arches. Completed in 1761, the highly successful canal extended deep into the coal field and became a much more efficient way to transport coal from the country to the city. The Bridgewater Canal cut the cost of coal in Manchester in half.
Work started in 1759 as small teams of skilled miners cut into rock by hand, using only picks, hammers, shovels, and drills. Later on, they used gunpowder to blast through the hard ground. The canal was carved at a downward sloping angle, a design that allowed gravity to pull mining boats through the majority of the long, underground chambers. In 1776, the canal was extended an additional 30 miles, from Manchester to Liverpool. Years later, numerous side-branching canals were added, creating the longest underground canal system in the world.Here's how this tunnel stacks up against some of the longest tunnels in the world.
(total length, in feet)