The Black Arrow by Robert Louis Stevenson

The passage in which Dick and Joanna now found themselves was narrow, dirty, and short. At the other end of it, a door stood partly open; the same door, without doubt, that they had heard the man unlocking. Heavy cobwebs hung from the roof; and the paved flooring echoed hollow under the lightest tread.

Beyond the door there were two branches, at right angles. Dick chose one of them at random, and the pair hurried, with echoing footsteps, along the hollow of the chapel roof. The top of the arched ceiling rose like a whale's back in the dim glimmer of the lamp. Here and there were spy-holes, concealed, on the other side, by the carving of the cornice; and looking down through one of these, Dick saw the paved floor of the chapel -- the altar, with its burning tapers -- and stretched before it on the steps, the figure of Sir Oliver praying with uplifted hands.