Blisworth Tunnel, on the Grand Union Canal, is:

• 3,075 yards (2,811 meters) long
• the longest wide, freely navigable tunnel in Europe (it's wide enough for two narrowboats to pass in opposite directions)
• the third-longest navigable canal tunnel in the UK, after Standedge and Dudley Tunnels
• the ninth-longest canal tunnel in the world
• about 143 feet (43m) below ground level
• roughly 18 miles (29km) from the northern end of the Grand Junction Canal at Braunston

And importantly, it's also just a short walk along the towpath at the Stoke Bruerne end from the Canal Museum, which holds great stories and memorabelia from the tunnel. Combine the two places to visit for a great day out.

We arrived by coach, and after a coffee break we were taken to the canal boat at the Blisworth Tunnel, located on the Grand Union Canal in Northamptonshire, England. This stretch is between the villages of Stoke Bruerne to the south and Blisworth to the north. The tunnel is 1.75 miles long, and is just passable for two boats as we experienced. Lunch at the boat Inn, a visit to the canal museum on the opposite side, then home again.