Near where I grew up there’s an abandoned quarry. For over a century bluestone was mined there. A deep open pit cut into the earth; steep walls of dark basalt criss-crossed by fine veins of quartz, caverns and sink holes and shelves of hard rock. Forty years ago the quarry stopped being profitable, so the mine owners turned off the pumps, removed the equipment that still worked, and let the ground water rise. Within a few months the quarry had turned into a lake. The rising tide submerged the void, and what was left behind was forgotten and drowned beneath the surface. The mining company planted some trees, put up a few picnic tables and walked away. Because of the height of the quarry walls on one side, the lake stood sheltered from the wind that whipped over the land, the skin of the water still and inviting, a dark blue pearl in an amphitheatre of stone.