Angel Island State Park, Tiburon, CA. You’ll fall in love with San Francisco all over again as you follow this hilly loop trail circumnavigating Angel Island. Along the way, savor the panoramic vistas of the Golden Gate Bridge, San Francisco, Alcatraz Island, the East Bay and Marin County. The 12K is a single loop. The 25K does the loop twice. Registration online at envirosports.com