"He showed him the secret catch in the bottom of the trough, a nailhead that sprung the trapdoor. He showed him how he wriggled through the small aperture, down into a hiding place carved in the earth beneath them. The room, not much more than six feet long, was a two-nun observation post. Its windows were just below the crest of the hill and were a great deal older than the dugout itself. They had originally been rabbit holes, which is what they still looked like from outside, although they had been carefully glazed and were now weatherproof They gave a clear view across the valley for miles."