Tunnel under Gunpowder Works, Camilty, West Lothian

This tunnel is under the gunpowder magazine of the old Camilty gunpowder mills. As you can see, it has collapsed in several places and is in a dangerous condition. The photo was taken during May 2012.
The technical information is as follows.
Camera - Canon EOS 5D Mk II
Shutter speed - 1/5
Aperture - f16.0
Lens - Canon EF 24 - 105mm f4.0 L IS USM
Focal Length 55mm
ISO 100
Canon 580EX II Flash with Roscolux Henna Sky Filter
Canon 420EX Flash with Roscolux Storaro Green Filter