Lobos Creek Valley is a quiet pocket of the Presidio, crossed by the last free-flowing stream left in San Francisco. The valley is not a headline sight, but it gives you a softer, more local side of the Presidio than the bridge viewpoints and former military posts.
Come for a short walk through dunes, scrub, and restored habitat, especially if you are already exploring Baker Beach or the western Presidio. It is best treated as a calm nature stop rather than a destination on its own.