There were loads of 'sand caves' in the side of hill near us, some quite deep. We were in and out of them all time. Makes me shudder to think what could have happened. There were also some holes in the side of the river Irwell valley which we crawled into. One had a chamber inside with a big rusty wheel on the ceiling. We spend hours trying to turn this wheel. Only many years later did I realise it was a sluice for when Fletchers canal, above it, was too full and needed draining into the Irwell. There must have been an equivalent 'wheel' above the surface. I'm pretty glad we never managed to move it:-)

Cheers

Dave the Gnome