We need the tonic of wildness...At the same time that we are earnest to explore and learn all things, we require that all things be mysterious and unexplorable, that land and sea be indefinitely wild, unsurveyed and unfathomed by us because unfathomable. We can never have enough of nature.
Henry David Thoreau, Walden: Or, Life in the Woods
environment, exploration, explore, land, mysterious, mystery, nature, sea, unexplorable, unfathomable, wild, wilderness, wildness