Below the grounds of Nottingham Castle and across the city there is a labyrinth of medieval tunnels, dungeons, maltings and cellars — people even carved primitive living quarters out of Nottingham’s sandstone cliffs.
The man-made caves, cut into the strata of rock known as Sherwood Sandstone, are being recorded by laser scanners, which produce up to 500,000 survey points a second, enabling us to see these excavations as never before.