This week we travel back in time through Standedge Tunnel to see how the much-loved monument looked over the years.
Located beneath the beautiful Pennine countryside, it's Britain's longest canal tunnel at 3.25 miles long, and is known as one of the Seven Wonders of the Waterways.
It first opened in April 1811 but was closed up in 1943, after which it fell into disrepair.
But after a £5m restoration programme it reopened in May 2001 as a tourist attraction.
And now boat trips into the dark depths of the tunnel are popular with visitors, boating fans and schoolchildren alike.
You can enjoy 30 minute trips every day, and trips all the way through to the other side to Diggle, which take two hours, are every other Saturday.
Click here to find out more about Standedge tunnel boat trips.
