If you're in San Francisco for just a day, a week, or even a lifetime, check out San Francisco City Guides walking tours.
Tours cover the rich history and architecture of neighborhoods all over the city. There's even a Hitchcock tour for movie buffs! Fun and family-friendly tours are free (although they happily accept donations) and are led by local volunteers who research and develop the tours.
This is a great way to explore hidden parts of the city and learn all the local lore. Participants meet at a designated spot—check the schedule online. Tours take place all year long, rain or shine. So tie on those walking shoes and learn more about this great city!