Although steep in sections, this trail is a wonderful workout and hikers are more than rewarded for their efforts. The Rock City Trail is a direct route to the summit of Mount Diablo, and the park is an ecological treasure dear to the hearts of Bay Area residents. The best views are on clear days immediately after rain or a storm - if you are lucky, you'll even be able to see the distant Sierra Nevada.

Photos: Miguel Vieira, Joe Lewis and Richard Conlan