Massive Caves on the Western Heights

On the Western Heights in Dover are these massive caves/mines. These may have been used to supply the mortar for the building of the western Heights fortifications 1800's part 1 of my video, we have to climb into the system with a rope, just to help us in. Inside we find so much graffiti in there from the mid 19th century In part 2 of my video we explore two more caves/mines to record the graffiti.