When was the last time you truly used, focused on, for any significant length of time, your imagination; your active, conscious, willful, artistic creativity, to get back in touch with that ability to appreciate the wonder that you yourself can create and bring forth, all from within yourself? Were you ever able to do that? Did you ever do that? Can you still do it? Do you do it when you game, as player or GM? Will you do it? Could this be missing from a lot of the newer, younger RPG'ers of today?
A little way up the narrow valley, before they reach the woods, the PCs notice the squat, tumbledown buildings by the riverside. They are hardly big enough for a human to stand in, and the complex cogs and shafts that occupy the central cavity of one of the buildings are perplexing. What were these buildings? And how safe are they to explore?
Alternatively a desolate place is the perfect setting for a derelict chapel or croft. There needn't be any actual physical encounter involved, but it adds atmosphere to a place to see its dead history. For instance, in the Outer Hebrides there are whole deserted villages which were razed to the ground by the English during the Clearances. Such stories give a setting authenticity and character.