The story
Welcome to a place where the modern world fades into a cool, subterranean silence. You are standing at the threshold of the Combe Down Tunnel, a remarkable feat of Victorian engineering and the centerpiece of the Two Tunnels Greenway here on the edge of Bath. As you prepare to enter, take a moment to look at the massive stone archway.
This was once the gateway for the Somerset and Dorset Joint Railway, a line affectionately known by locals as the Slow and Dirty. Today, however, it serves a much quieter purpose as the longest cycling and walking tunnel in all of Britain. As you step inside, you’ll immediately feel the temperature drop.
Even on a scorching summer day, the air in here remains a steady, damp chill. You are about to travel over a mile into the darkness, moving directly beneath the honey-colored stone houses of Combe Down village. For the next twenty minutes or so, the only sounds you’ll hear are the rhythmic clicking of bicycle gears, the steady beat of your own footsteps, and the haunting resonance of water dripping from the soot-stained bricks above.
The tunnel was opened in 1874, carved through the solid oolite limestone by men working with little more than gunpowder and pickaxes. For nearly a century, steam engines thundered through this narrow space, choking it with thick, black smoke. When the line was closed in the 1960s, the tunnel was sealed and forgotten for decades, left to the shadows and the echoes.
It wasn’t until 2013 that it was reclaimed for the public, and that sense of history still clings to the walls. About halfway through your journey, the atmosphere begins to shift. You’ll notice the standard amber safety lights give way to something far more ethereal.
This is Tideline, a hidden sound-and-light installation by United Visual Artists. As you reach the very center of the hill, where the darkness is at its heaviest, twenty synchronized lamps begin to pulse with a soft, ghostly blue glow. Accompanying the light is a delicate, choral soundscape that swells and fades, mimicking the movement of the tides.
It is a surreal experience—standing in the pitch-black heart of a mountain, surrounded by a phantom ocean of sound. As you eventually leave the artwork behind and move toward the far end, keep an eye out for the tiny dot of white light ahead. It grows slowly, eventually revealing the lush, green canopy of the Midford Valley.
When you finally emerge back into the daylight, the birdsong and the warmth of the sun will feel like a celebration. You’ve just walked through a mile of history, a hidden artery of the English countryside that remains one of Bath’s most atmospheric secrets. Enjoy the rest of your journey along the Greenway.