"The unknown is so inflammatory to the imagination because it is an imaginatively malleable space: a projection-screen on to which a culture or an individual can throw their fears and their aspirations. Like Echo's cave, the unknown will answer back with whatever you shout at it. The blank spaces on a map -- 'blank spaces for a boy to dream gloriously over', as Joseph Conrad once called them -- can be filled with whatever promise or dread one wishes to ascribe to them. They are places of infinite possibility. The pungent longing I felt for that immaculate valley beyond the ridge was a longing for my own disguised dreams. And my dreams, of course, were driven by the desire to go somewhere no one had gone before, to do something no one had done before: the desires for priority and originality which are so deeply entrenched in the Western imagination." --
Robert Macfarlane, in his simultaneously exciting and meditative Mountains of the Mind, a natural and cultural history, a memoir, and an exploration of an obsession.