Stretching 2997 yards under the Northamptonshire countryside, I couldn't turn down a chance to peer into the black hole before it is developed into a wind tunnel for the motor industry. Was only allowed afew metres inside due to roosting bats but had a good look and was told about their plans to create one of if not the best wind tunnel in Europe. Afterwards we took a slight detour to go and locate Catesby viaduct. Anyway.... here's some pics.