04 Aug 2016
Found in the hills of Saddleworth above Dovestones reservoir is a mile long culvert built to divert the water of the Greenfield brook straight into Dovestone Reservoir. It's around 10ft tall and pretty much dead straight.
Around midway a pipe drops a substantial flow into the culvert, shortly after a hole in the crown of the brick lining allows the blasted rock outer tunnel to be seen.
The event horizon.