Honour knew there were caves inside Canterlot mountain -- everypony knew that -- but she’d never imagined any of them looked like this. The spiral passage had deposited them at the edge of a narrow, fifty-hoof cliff, and from it they looked out over a roughly circular cavern that must have been two hundred hooves wide. On the right, a triple waterfall cascaded down from a narrow crack in the ceiling, pouring water into a river that snaked along the cavern floor before it disappeared under a rocky shelf to the left. Above, two huge, spherical iron cages, suspended on black chains from the ceiling, glowed with powerful, white arcane light.