Fifteen feet beneath a modest house, behind an average door on Drum Street in Gilmerton, near Liberton in south Edinburgh, lies a network of seven chambers and numerous tunnels hand-carved from the sandstone beneath the streets.
Ever since the discovery of the mysterious and historic site, the tunnels' intended purpose has remained a mystery to both archaeologists and casual observers alike for three hundred years.
And interestingly, a recent ground penetration survey has indicated that the caves are significantly larger than previously estimated, possibly up to twice as large - but some are inaccessible.
