Mt. Tamalpais, or "Mt. Tam," was a sacred spot for Native Americans, who saw in its profile the outline of a woman in repose. The 6,300-acre park that surrounds this gentle peak has more than 200 miles of trails, ranging in difficulty from modest to steep and crossing a variety of landscapes. The park was also the birthplace of mountain biking in the 1970s, and its winding trails are still a big hit with bikers, so keep an eye out for quick-moving spandex.